01 - Preheat oven to 400°F. Lightly grease a baking dish large enough to arrange tilapia fillets in a single layer.
02 - Pat each tilapia fillet dry using paper towels. Arrange fillets in the prepared dish and lightly brush both sides with olive oil.
03 - In a small bowl, whisk together melted butter, minced garlic, lemon juice, lemon zest, chopped parsley, salt, and black pepper until well combined.
04 - Pour the lemon butter mixture evenly over the tilapia fillets, ensuring thorough coating on each piece.
05 - Place a lemon slice atop each fillet for added flavor and presentation.
06 - Bake in the preheated oven for 15 to 20 minutes, or until the fish flakes easily with a fork and appears opaque throughout.
07 - Remove from the oven, garnish with additional chopped parsley if desired, and serve immediately.