Place cauliflower in a microwave-safe baking dish with just enough water to cover bottom of dish. Cook in the microwave on High for 5 minutes, or until slightly tender. Drain, and season with salt and pepper. Arrange tomato slices around the cauliflower. Drizzle cauliflower and tomatoes evenly with melted butter, and top with cheese.
Bake 40 minutes in the preheated oven, until cheese is bubbly.
