Baked Flounder With Parmesan Crumbs

4 flounder fillets (1 1/2 to 2 pounds total) (may substitute cod, haddock or orange roughy)
Salt and freshly ground black or white pepper, to taste
4 tablespoons unsalted butter
1/2 cup finely crumbled fresh bread crumbs
3/4 cup (3 ounces) finely grated Parmesan cheese
2 tablespoons extra-virgin olive oil
Freshly grated lemon zest or freshly squeezed lemon juice (optional)
Thinly sliced fresh basil leaves (optional)

Preheat the oven to 425 degrees.
Pat the fish dry. Place the fillets in a large baking dish or roasting pan and season with salt and pepper to taste. Set aside.

In a small skillet over low heat or in a microwave-safe bowl, melt the butter. Add the bread crumbs, cheese and oil and, using your fingers, mix until evenly combined. Sprinkle the mixture evenly over the fillets.

Bake the fillets until they are cooked through and the topping is golden, about 15 minutes. Let stand for 5 minutes. If desired, sprinkle with lemon zest or juice and basil. Serve hot.