Step 1

Heat oven to 425 degrees. Heat oil in a 12-inch ovenproof skillet over medium-high. Crumble sausage into skillet, using a spoon to break it into small pieces. Cook until starting to brown, stirring occasionally, 5 to 7 minutes. Stir in garlic, oregano, fennel seeds and red-pepper flakes (if using), and cook another 1 to 2 minutes.

Step 2

Stir in whole tomatoes and their juice, using a spoon to break them up. Add crushed tomatoes, bay leaves and 2 teaspoons salt, and bring to a simmer. Simmer for 10 minutes to thicken slightly.

Step 3

Stir in pasta and 1 cup water and return to a simmer. Continue to simmer for 2 minutes, stirring frequently to make sure pasta doesn’t stick to the bottom of the pan. Remove from heat, pluck out the bay leaves, and fold in about a third of the mozzarella.

Step 4

Top pasta with remaining mozzarella and dollops of ricotta. Sprinkle with Parmesan, then transfer to oven. Bake until pasta is tender when poked with a fork, and cheese is bubbly and lightly golden, 18 to 22 minutes. (If you’d like a more deeply browned topping, run the pan under the broiler for 1 or 2 minutes.) Remove from oven and let cool slightly before serving. Top with basil, plenty of black pepper, and more red-pepper flakes, if you like.