Let me transport you to a cozy Saturday evening a few years ago. I was craving something special, something that felt like a departure from our usual pizza and pasta weekend routine. I wanted a meal that was impressive, comforting, and packed with flavor. That’s when I stumbled upon the magic of phyllo dough. I decided to create a casserole that would combine the flaky, buttery layers of phyllo with a rich, savory filling inspired by Greek flavors. The result was this Spinach and Havarti Phyllo Casserole. The moment it came out of the oven, golden and puffed, my family was gathered around the kitchen island, unable to resist its aroma. That first bite; crispy, flaky layers giving way to a creamy, spicy, cheesy filling; was pure magic. It’s been a cherished recipe ever since, perfect for everything from holiday brunches to cozy weeknight dinners. It’s proof that with a little patience and phyllo, you can create something truly spectacular.
Let’s talk about the incredible flavor and texture in this dish. It’s a savory, slightly spicy, and utterly satisfying masterpiece. The filling starts with spicy Italian chicken sausage, which adds a wonderful kick. This is balanced by the creamy, mild, and slightly nutty Havarti cheese, along with sharp cheddar and gooey mozzarella. Earthy spinach, briny kalamata olives, and tangy sun dried tomatoes add layers of complexity. A mixture of eggs and Greek yogurt creates a rich, custardy binder, while fresh basil and thyme bring aromatic freshness. But the true star is the 40 layers of phyllo dough, each brushed with oil or butter, baking into a deeply golden, impossibly flaky, and crisp crust that shatters beautifully with every bite. It’s a symphony of textures and tastes that’s absolutely unforgettable.
Secrets to Phyllo Perfection
These pro tips are your guarantee for a flawless, showstopping casserole.
- Thaw Phyllo Properly: This is crucial. Thaw frozen phyllo overnight in the refrigerator. Let it come to room temperature for about an hour before using, still in its packaging, to prevent it from becoming too brittle and cracking.
- Work Quickly and Keep It Covered: Phyllo dries out almost instantly when exposed to air. As soon as you unroll the sheets, cover the stack with a lightly damp (not wet!) paper towel or a clean kitchen towel. Remove sheets one at a time as you need them, and always re cover the stack.
- Don’t Skimp on the Oil or Butter: Brushing each layer generously with oil or melted butter is what gives phyllo its signature flaky, golden crust. Be thorough, but you don’t need to soak it; a light, even coat is perfect.
- Drain Your Spinach Really Well: This is the most important tip for the filling. Frozen spinach holds a tremendous amount of water. After thawing, place it in a clean kitchen towel and squeeze firmly to remove every last drop of excess liquid. A dry filling is the key to a casserole that isn’t watery.
Make Ahead, Storage & Freezing Instructions
This dish is a meal prep and entertaining dream.
- Make Ahead Champion: You can assemble this casserole completely (without baking) up to 3 days in advance. Cover it tightly with plastic wrap and store it in the refrigerator. When you’re ready to bake, simply remove the plastic wrap and bake as directed, adding 10-15 minutes to the total bake time since you’re starting from cold.
- Storing Leftovers: Store any leftover baked casserole in an airtight container in the refrigerator for up to 4 days. The phyllo will soften slightly, but it will still be delicious.
- Reheating: For best results, reheat individual portions in a toaster oven or air fryer at 350°F for a few minutes to re crisp the phyllo. You can also reheat in a conventional oven, covered, at 325°F until warmed through. The microwave will work but will make the phyllo soft.
- Freezing Instructions: This casserole freezes beautifully! For best results, line your baking dish with foil before assembling, allowing extra foil to hang over the edges. Assemble the casserole in the foil lined dish, then freeze until solid. Use the foil overhang to lift the frozen casserole out of the dish, wrap it tightly in another layer of plastic wrap and foil, and return it to the freezer for up to 3 months. To bake, unwrap the frozen casserole, place it back in the original baking dish, and thaw overnight in the refrigerator. Bake as directed.
Step by Step Instructions
Prep Time: 30 minutes | Cook Time: 1 hour – 1 hour 15 minutes | Total Time: ~1 hour 45 minutes
Follow these detailed steps for a perfect, beautiful casserole.
1Preheat and Prep: Preheat your oven to 350°F (177°C). Have a 9×13 inch glass or ceramic baking dish ready. (No need to grease it yet, as the phyllo will be oiled.)
2Cook the Sausage: In a large skillet, heat 1 tablespoon of olive oil over medium heat. Remove the casings from the spicy Italian chicken sausage and add the sausage meat to the skillet. Cook, breaking it up with a spoon, until it’s browned and cooked through (about 5-7 minutes). Remove from heat and set aside.
3Prepare the Filling Mixture: In a large bowl, whisk the 5 eggs well. Add the ½ cup of Greek yogurt and whisk until smooth. Stir in the chopped fresh basil (or dried), fresh thyme, 1 tablespoon of black pepper, a pinch of salt, and the crushed red pepper flakes.
4Combine Filling: Add the cooked sausage and the well drained frozen spinach to the bowl. Mix until everything is thoroughly combined. Set aside.
5Prepare the Olives and Tomatoes: In a small bowl, combine the sliced kalamata olives and the oil packed sun dried tomatoes. (If your sun dried tomatoes don’t have garlic, you may want to add a minced clove to the sausage while it cooks.)
6Layer the Phyllo (First Layer): Unroll the thawed phyllo sheets and cover the stack with a damp paper towel. Place one sheet of phyllo in the bottom of your 9×13 baking dish. Brush it lightly but thoroughly with canola oil (or melted butter). Repeat this process, adding eight more phyllo sheets (for a total of 9 sheets in the first layer), brushing each one with oil.
7Add First Layer of Fillings: Sprinkle half of the shredded cheddar cheese evenly over the phyllo. Then, dollop half of the spinach sausage mixture over the cheddar. Top with half of the Havarti cheese and half of the olive and sun dried tomato mixture.
8Layer the Phyllo (Second Layer): Now, layer nine more phyllo sheets on top, just as before, brushing each one with oil.
9Add Second Layer of Fillings: Sprinkle the remaining cheddar cheese over this phyllo layer. Then, add the rest of the spinach sausage mixture, followed by the remaining Havarti cheese and the rest of the olives and tomatoes.
10Layer the Phyllo (Third Layer): Layer eight more phyllo sheets on top, brushing each with oil. After these eight, sprinkle the shredded mozzarella cheese evenly over the top.
11Final Phyllo Layer: Layer the remaining phyllo sheets (you should have about 14 left) on top of the mozzarella, brushing each one with oil. Don’t worry if the top is a little uneven; it will bake into a beautiful, rustic crust.
12Bake: Place the casserole in the preheated oven and bake for 1 hour to 1 hour and 15 minutes, until the top is deeply golden brown and crisp, and the filling is hot and bubbly.
13Rest and Serve: Let the casserole rest for at least 15-20 minutes before slicing and serving. This allows it to set and makes for much cleaner slices.
Customize It: Ingredient Substitutions
This recipe is wonderfully adaptable to different tastes and dietary needs.
- Gluten Free: Unfortunately, traditional phyllo dough is made with wheat flour and is not gluten free. You could potentially experiment with gluten free phyllo if you can find it, but I haven’t tested it. The filling itself is gluten free, so you could serve it as a crustless frittata style casserole in a well greased dish.
- Dairy Free: This is a challenge due to the cheese and yogurt. For a dairy free version, you would need to use high quality vegan alternatives for the Havarti, cheddar, mozzarella, and Greek yogurt. The texture and flavor would be different. Substitute the butter/oil with a vegan butter or more olive oil.
- Vegetarian: Easily make this vegetarian by omitting the sausage. You could add more vegetables, like sautéed mushrooms or zucchini, or even a can of drained chickpeas for extra protein.
- Protein Swaps: Not a fan of chicken sausage? Use spicy Italian pork sausage for a richer flavor. Ground turkey with added spices would also work.
- Common Pantry Swaps:
- Cheese: Havarti is creamy and mild, but you could substitute with fontina, provolone, or even a good melting Gruyère. Any good melting cheese will work.
- Olives: No kalamata? Use chopped Castelvetrano or even oil cured black olives.
- Sun Dried Tomatoes: If you only have dry packed sun dried tomatoes, rehydrate them in hot water for 20 minutes, then drain and chop before using.
- Spinach: While frozen spinach is easiest, you could use 1-2 pounds of fresh spinach, wilted in a pan, then squeezed absolutely dry.
- Oil for Brushing: Canola oil is great for a neutral flavor, but melted butter will give you an even richer, more golden, and flakier crust. A mix of both is also wonderful.
Serving Suggestions: How to Enjoy Your Casserole
This dish is a star all on its own, but here’s how to make it a meal.
- For Brunch or Lunch: Serve it with a simple mixed green salad tossed with a lemon vinaigrette to cut through the richness. A side of fresh fruit is also lovely.
- For Dinner: Pair it with roasted vegetables like asparagus, broccoli, or a medley of bell peppers and onions. A light soup, such as tomato or lentil soup, would also be perfect.
- As an Appetizer: Cut the baked casserole into small, bite sized squares and serve them as a stunning passed appetizer at a party.
- Beverage Pairings: The bold, savory flavors are a perfect match for a crisp, dry white wine like Sauvignon Blanc or Pinot Grigio. A light lager or pilsner would also be excellent. For a non alcoholic option, sparkling water with a twist of lemon or iced tea is refreshing.
Essential Equipment List
- 9×13 Inch Glass or Ceramic Baking Dish: The perfect size for this casserole.
- Large Skillet: For browning the sausage.
- Large Mixing Bowl: For combining the filling ingredients.
- Small Bowl: For the olives and tomatoes.
- Pastry Brush: Essential for evenly brushing the phyllo sheets with oil or butter.
- Clean Kitchen Towel or Paper Towels: For covering the phyllo and for squeezing the spinach dry.
- Chef’s Knife and Cutting Board
- Measuring Cups and Spoons
Frequently Asked Questions (FAQ)
- What is phyllo dough? Where can I find it?
Phyllo (or filo) dough is very thin, unleavened dough used in many Mediterranean and Middle Eastern pastries. It’s typically sold frozen in the dessert or freezer section of most major grocery stores, often near the puff pastry. Look for it in a long, flat box. - Can I use butter instead of oil for brushing the phyllo?
Absolutely! Melted butter will give you an even richer flavor and a deeply golden, flaky crust. You can use all butter, or a combination of butter and oil. Just make sure it’s melted and slightly cooled for easy brushing. - Where do the sun dried tomatoes go?
The recipe instructions originally missed this step. You should mix the sliced sun dried tomatoes in with the kalamata olives, and add them in the layers as directed for the olives. This ensures their flavor is distributed throughout the filling. - My casserole is browning too quickly on top. What should I do?
If the top is getting too dark before the filling is cooked through, you can loosely tent the casserole with a piece of aluminum foil for the remainder of the baking time. This will prevent the top from burning while the inside finishes cooking. - Can I prepare this with fewer phyllo layers?
The many layers are what make this casserole so spectacular and sturdy. Reducing the number of layers may result in a less impressive crust and could make the casserole harder to slice and serve. I recommend sticking to the recipe for the full effect!
Spinach and Havarti Phyllo Casserole
Ingredients
- 1 tablespoon olive oil
- 1 lb spicy Italian chicken sausage casings removed
- 5 large eggs
- ½ cup kalamata olives sliced
- ½ cup oil packed sun dried tomatoes drained and chopped
- 1 10 oz package frozen chopped spinach, thawed and squeezed completely dry
- ½ cup plain Greek yogurt
- 2 tablespoons fresh basil chopped (or 2 teaspoons dried)
- 1 teaspoon fresh thyme leaves or ½ teaspoon dried
- 1 tablespoon black pepper
- 1 pinch salt
- 1 teaspoon crushed red pepper flakes
- 2 ½ cups Havarti cheese shredded
- ½ cup cheddar cheese shredded
- ½ cup mozzarella cheese shredded
- 1 16 oz package phyllo pastry sheets, thawed (about 40 sheets)
- ½ cup canola oil or melted butter for brushing
Instructions
- Cook Sausage: Heat olive oil in a large skillet over medium heat. Add sausage and cook, breaking it up, until browned and cooked through (5-7 minutes). Set aside.
- Make Filling: In a large bowl, whisk eggs and Greek yogurt until smooth. Stir in basil, thyme, black pepper, salt, and red pepper flakes. Add cooked sausage and squeezed dry spinach. Mix until combined.
- Prepare Olives & Tomatoes: In a small bowl, combine sliced olives and chopped sun dried tomatoes. Set aside.
- Preheat & Prep Phyllo: Preheat oven to 350°F (177°C). Unroll phyllo sheets and cover stack with a damp paper towel to prevent drying.
- First Phyllo Layer: Place 1 phyllo sheet in a 9x13 baking dish. Brush lightly with oil. Repeat with 8 more sheets, brushing each with oil (9 sheets total).
- First Filling Layer: Sprinkle half the cheddar cheese over the phyllo. Dollop half the spinach sausage mixture over the cheddar. Top with half the Havarti cheese and half the olive tomato mixture.
- Second Phyllo Layer: Layer 9 more phyllo sheets on top, brushing each with oil.
- Second Filling Layer: Sprinkle remaining cheddar over phyllo. Add remaining spinach sausage mixture, then remaining Havarti and olive tomato mixture.
- Third Phyllo Layer: Layer 8 more phyllo sheets on top, brushing each with oil. Sprinkle mozzarella cheese evenly over these sheets.
- Final Phyllo Layer: Layer remaining phyllo sheets (about 14) on top, brushing each with oil.
- Bake: Bake for 60-75 minutes, until the top is deep golden brown and crisp, and the filling is hot and bubbly.
- Rest & Serve: Let casserole rest for at least 15-20 minutes before slicing and serving.
Notes
- Drain Spinach Well: Squeeze all excess moisture from the thawed spinach using a clean kitchen towel. This is crucial to prevent a watery casserole.
- Make Ahead: Assemble unbaked casserole up to 3 days ahead; cover and refrigerate. Bake as directed, adding 10-15 minutes.
- Freezing: Line baking dish with foil before assembling; freeze, then remove from dish and wrap tightly. Freeze for up to 3 months. Thaw overnight before baking.
- Sun Dried Tomatoes: If your tomatoes aren't packed with garlic, add 1 minced garlic clove to the sausage while it cooks.
