Tomato and Cheese Grits

Ingredients: 1 cup quick-cooking grits 4 cups water or chicken broth 1 cup shredded cheddar cheese 1/2 cup grated Parmesan cheese 1 can (14.5 oz) diced tomatoes, drained 1/4 cup heavy cream 2 tbsp butter 1/2 tsp salt 1/2 tsp black pepper