Preheat oven to 425 degrees F. Line a rimmed baking sheet with foil (for easy clean up) and spray with cooking spray.
Place fish on the prepared baking sheet. Pat dry with paper towels. Season with salt and pepper.
In a small bowl, whisk together melted butter, lemon juice, garlic powder and salt. Brush butter mixture onto the fillets.
Bake, uncovered, for 10-15 minutes (or until the fish flakes easily with a fork). For a crispier exterior, place the fish under the broiler for the final 2-3 minutes of baking. Garnish with parsley and serve with lemon wedges.
Notes
To make crispy tilapia, you can transfer the fish to the broiler for the final 2-3 minutes of cooking time.
Can you reheat baked tilapia? While it's not ideal, you can carefully reheat the tilapia. You just need to be sure that you don't overcook the fish in the reheating process. Either warm in the microwave for just a few seconds, or warm in a 275 degree F oven (loosely covered with foil) for about 7-10 minutes (or until the fish reaches an internal temperature of 135-130 degrees F).
If you like the flavor of Old Bay seasoning, you can add a dash of Old Bay to the melted butter mixture and then brush it on the fish.
If you're cooking just for two people, cut the ingredients in half and bake two tilapia fillets instead of four.
If you're starting with frozen tilapia and you don't have time to thaw the fish in the refrigerator before baking, that's fine! You can bake tilapia from frozen with this recipe, and just increase the baking time until your fish is cooked through.