Baked Tilapia For each two Tilapia filets, use: 1/4 cup margarine or butter, 3 tablespoons of unsweetened orange juice, 3 tablespoons of finely chopped onion, a pinch of garlic salt and a sprinkle of parsley flakes. Heat and stir this mixture until the margarine is liquified and cover the bottom of a 9 X 13 baking dish with the sauce. Lay in the Tilapia fillets and apply additional sauce to the top of the fillets as well as a sprinkle of finely grated cheddar cheese. Bake in the covered baking dish at 325 for 45 minutes. Serve with a side of hash brown or mashed potatoes with additional parsley flakes and a side of long cut asparagus.