Preparation Preheat oven to 350°F. Oil 11x7-inch baking dish. Heat 2 tablespoons oil in heavy large skillet over medium heat. Add garlic and sauté until fragrant, about 30 seconds. Add onion and sauté until soft, about 6 minutes. Add tomatoes, reduce heat to medium-low, and cook until beginning to soften, about 5 minutes. Mix in chives; season with salt and pepper. Transfer tomato mixture to prepared baking dish; sprinkle grated cheeses over. Bake until cheese melts and begins to turn golden, about 20 minutes.
Preparation Preheat oven to 350°F. Oil 11x7-inch baking dish. Heat 2 tablespoons oil in heavy large skillet over medium heat. Add garlic and sauté until fragrant, about 30 seconds. Add onion and sauté until soft, about 6 minutes. Add tomatoes, reduce heat to medium-low, and cook until beginning to soften, about 5 minutes. Mix in chives; season with salt and pepper. Transfer tomato mixture to prepared baking dish; sprinkle grated cheeses over. Bake until cheese melts and begins to turn golden, about 20 minutes.