Yield:4 to 6 servings

• Kosher salt (such as Diamond Crystal) and freshly ground black pepper

• 1 pound rigatoni 

• 2 teaspoons olive oil

• 1 pound hot or sweet Italian chicken sausage (or Italian pork sausage), casings removed 

• 4 tablespoons unsalted butter

• 3 tablespoons all-purpose flour

• 2 cups milk

• 3 garlic cloves, grated

• 3 tablespoons grated lemon zest, plus 6 tablespoons lemon juice (from about 3 lemons)

• 1 cup ricotta 

• ½ cup grated Parmesan

• 2 cups baby spinach

• 1 cup/4 ounces shredded mozzarella 

• 8 ounces fresh mozzarella, sliced

• For garnish

• Basil leaves

• Crushed red pepper

• Lemon zest

1. Step 1

   Heat oven to 350 degrees. 

2. Step 2

   Bring a large pot of generously salted water to a boil. Boil the pasta until al dente according to the package’s instructions. Reserve ¾ cup of pasta water and then drain the pasta.

3. Step 3

   In a large (preferably ovenproof) skillet over medium-high heat, heat the olive oil. Once hot, add the sausage and cook, breaking it up with a wooden spoon until it’s cooked through and lightly browned. Remove the sausage from the pan.

4. Step 4

   In the same pan (no need to wash it), lower the heat to medium-low and add the butter. Once the butter has melted, add the flour and stir for 1 minute, allowing the flour to become fragrant and nutty. Slowly stir in the milk, gently picking up any bits that have stuck to the pan.

5. Step 5

   Next, mix in the grated garlic, lemon zest and reserved ¾ cup pasta water. Stir until a thick sauce comes together that coats the back of a spoon; 2 to 4 minutes. Remove the sauce from the heat and immediately stir in the ricotta, Parmesan, lemon juice, 1½ teaspoons salt and ½ teaspoon black pepper. Taste the sauce for seasoning, adding more salt as needed.

6. Step 6

   Add the drained pasta to the sauce along with the chicken sausage, spinach and shredded mozzarella. Give it a good mix until the pasta is fully coated in the sauce. If your pan isn’t ovenproof, transfer the pasta mixture to a 9-by-13-inch baking dish (or other 3-quart baking dish).

7. Step 7

   Cover the top with the slices of fresh mozzarella. Cover with foil and bake for 20 minutes, then remove foil and broil for 2 to 3 minutes, until the mozzarella topping is melted with golden brown flecks. Garnish with basil leaves, crushed red pepper and more lemon zest to taste before serving.

or to mark this recipe as cooked.