Heat oil, garlic, pepper flakes, and sugar in 12-inch nonstick skillet over medium-high heat until fragrant and sizzling, about 1 minute. Stir in tomatoes and cook until they just begin to soften, about 1 minute. Season to taste with salt and pepper and remove from heat. Spoon tomato mixture with any accumulated juices over polenta, top with mozzarella, and sprinkle with basil before serving.

Makes enough for 4 servings