Preheat the oven to 375 degrees . Grease a 9x13 baking dish.
Next, heat a pan on medium-high heat, add 1 tsp of butter and start sauteing the onions till they are nice and caramelized.
Place the tilapia fillets in the baking dish and dot with the remaining butter. Season with Old Bay seasoning and garlic salt. Top each one with a slice or two of lemon. Arrange the frozen mixed vegetables around the fish, and season lightly with salt and pepper.
Cover the dish and bake for 25 to 30 minutes in the preheated oven, until vegetables are tender and fish flakes easily with a fork.
Serve with rice and broccoli, and sauteed onions.
Servings: 4 | Calories: 126cal | Fat: 2.4g | Saturated Fat: 1.4g | Cholesterol: 19mg | Sodium 104mg | Carbohydrates: 17.7g | Fiber: 5.6g | Sugar: 4.8g | Protein: 8.9g | Vitamin D: 1mcg | Calcium: 41mg | Iron: 1mg | Potassium: 236mg