Food & Cooking Recipes Breakfast & Brunch Recipes Tomato-Onion Casserole 3.7 (53) Close Credit: Con Poulos Prep Time: 10 mins Total Time: 55 mins Servings: 8 If you're a fan the juicy flavor of roasted tomatoes, this easy brunch dish is for you. Directions Preheat oven to 450 degrees. In a 9-by-13-inch baking dish, arrange tomatoes and onions in rows, overlapping slightly. Drizzle with oil and season with salt and pepper. Bake until tomatoes are lightly browned and onions are tender, about 45 minutes. Serve warm or at room temperature.