Step 1

Bring a large pot of water to a boil for the rigatoni. Once boiling, add the pasta, and continue to boil until tender. Drain in a colander and set aside until needed.

Step 2

After starting the pasta water, begin the sauce. Add the olive oil and minced garlic to a large skillet and sauté for about one minute over medium heat, or just until the garlic becomes fragrant. Add the sliced mushrooms, a pinch of salt and pepper, and continue to sauté until the mushrooms have released all their moisture and begin to brown on the edges (about 5-7 minutes).

Step 3

Add the sauce to the skillet. Stir the sauce as it heats, dissolving any browned bits off the bottom of the skillet. Once the sauce is heated through, add the spinach, and continue to stir and cook until the spinach has wilted (about 5 minutes more).

Step 4

Once the rigatoni has been cooked and drained, stir it into the skillet with the sauce and vegetables and allow everything to heat through.

Step 5

In a small bowl, stir together the ricotta, Parmesan, and a pinch of salt and pepper. Add the ricotta mixture to the skillet, in dollops over the surface. Gently fold the ricotta into the pasta, leaving it only about half mixed, so there are still pockets of ricotta within the sauce and pasta.

Step 6

Sprinkle the shredded mozzarella over the pasta, place a lid on the skillet, and let it heat over medium-low until the cheese is melted. If you want the cheese to brown a bit, place it under your oven's broiler (without a lid) and watch closely until it develops a few browned spots. Serve hot.