Prep the Vegetables: Place the chopped sweet potatoes and carrots in a medium saucepan and cover with water. Bring to a boil and cook until tender but still slightly firm (not mushy), about 8-10 minutes. Drain and set aside.
Preheat and Prep Dish: Preheat your oven to 400°F (200°C). Lightly grease a 2 quart casserole dish or four 10 ounce ramekins with cooking spray. Place on a baking sheet to catch any drips.
Start the Filling: In a large skillet over medium heat, heat the 1 tablespoon olive oil. Add the chopped onion and sauté until softened and translucent, about 5 minutes.
Make the Roux: Sprinkle the ¼ cup all purpose flour over the onions. Cook, stirring constantly, for 1 minute to cook out the raw flour taste.
Create the Gravy: Slowly pour in the vegetable broth while whisking vigorously to prevent lumps. Continue to cook over medium heat, whisking often, until the mixture thickens and begins to bubble, about 2 to 3 minutes.
Combine Filling: Stir in the cooked chickpeas, frozen peas, cooked sweet potatoes, cooked carrots, salt, pepper, and a dash of Tabasco sauce. Cook for 2 to 3 minutes more until heated through. Taste and adjust seasoning as needed. Pour the filling into the prepared casserole dish or divide evenly among the ramekins.
Make the Cornbread Crust: In a medium mixing bowl, whisk together the cornmeal, ¾ cup all purpose flour, baking powder, sugar, and salt. In a separate small bowl or liquid measuring cup, combine the milk, olive oil, and beaten egg yolk.
Combine Wet and Dry: Pour the wet ingredients into the dry ingredients. Stir with a spatula just until combined and no dry streaks remain. The batter will be slightly lumpy; do not overmix.
Top and Bake: Spoon the cornbread batter evenly over the warm filling, spreading gently to cover the surface.
Bake: Bake until the cornbread crust is golden brown and a toothpick inserted into the topping comes out clean. For a 2 quart casserole, bake for 22 to 25 minutes. For individual ramekins, bake for 12 to 15 minutes.
Serve: Let the potpie stand for 5 minutes before serving. The filling will be extremely hot.