Position a rack in the center of the oven and preheat to 400 degrees . Grease a 1 1/2-quart shallow casserole dish. Using a food processor, pulse the tomato halves, salt, sugar and a pinch of pepper until coarsely pureed.
Place the bread cubes in the prepared dish and pour in the melted butter to coat. Top with the tomato puree and gently mix to distribute.
Bake until crusty and golden brown, about 30 minutes. Sprinkle the cheese on top and bake for 10 minutes more. Let cool for 5 minutes before serving.