Arrange a rack in the middle of the oven and preheat to 425°F.
Coat a 9x13 inch baking dish with 1 tablespoon of the butter.
Place the cod fillets in the prepared baking dish. Squeeze the juice from 2 lemon wedges over the fish, then season generously with Kosher salt and black pepper.
In a small skillet over medium low heat, melt the remaining 4 tablespoons of butter. Watch it closely; as soon as the butter melts and just begins to foam, turn off the heat completely.
Immediately add the minced garlic to the warm butter. Allow the garlic to infuse the butter for 1 minute off the heat. Do not let the garlic brown.
Add the panko breadcrumbs to the skillet and toss lightly with a fork until all the butter is fully absorbed and the mixture resembles wet sand.
Stir in the chopped fresh parsley and season the panko mixture lightly with a pinch of salt and pepper.
Evenly divide the panko mixture over the top of each cod fillet, gently pressing down so the crust adheres.
Bake, uncovered, until the panko crumbs are deep golden brown and the fish is just cooked through, about 12 to 15 minutes. The fish is ready when it flakes easily with a fork and an instant read digital thermometer inserted into the thickest part of the fillet registers 145°F.
Remove from the oven and serve immediately with the remaining fresh lemon wedges on the side.