Step 1

Place an oven rack in the middle position. Preheat the oven to 400 degrees F.

Step 2

Bring a large pot of salted water to a boil over medium-high heat.

Step 3

Heat a tablespoon of the oil in a large, shallow braiser over medium heat. Add the sausage. Using a wooden spoon, break up the sausage into bite-sized pieces and cook until browned, 8 to 10 minutes. Remove to a bowl with a slotted spoon. Add the cherry tomatoes into the braiser and cook, stirring occasionally, until they just start to lose their shape, 2 to 3 minutes. Add the spinach and season with 1/2 teaspoon of salt. Stir and cook until the tomatoes begin to burst and the spinach is wilted but still bright green, about 3 minutes more. Remove the tomatoes and spinach to the bowl with the sausage.

Step 4

To make the sauce: Add the remaining 2 tablespoons of oil and the butter into the now empty braiser. Once the butter is melted, add the garlic and cook until sizzling, about 30 seconds. Sprinkle in the flour and stir to make a paste. Cook for 1 minute and then whisk in the cream and milk. Bring to a boil, then reduce to a simmer. Stir in the oregano and remaining 1 1/2 teaspoon salt. Simmer until thickened, 5 to 6 minutes.

Step 5

Meanwhile, add the pasta to the boiling water and undercook by 2 to 3 minutes short of the package instructions. Drain, reserving 1/2 cup of the pasta cooking water.

Step 6

Stir 1/2 cup of the Pecorino Romano into the sauce and add the pasta. Add the sausage, tomatoes and spinach. Toss to evenly coat everything in the sauce, adding a little of the pasta water if it seems dry. Sprinkle with the remaining 1/2 cup Pecorino Romano and dollop the ricotta in spoonfuls all around the top. Finish with a final drizzle of olive oil.

Step 7

Bake until browned and bubbly, about 25 minutes. Remove from the oven and allow to cool slightly before serving. Season with crushed red pepper flakes and freshly ground black pepper.

Step 8

The pasta is best eaten as soon as it’s made but will keep covered for 2 days in the refrigerator.