Step 1

Preheat the oven to 425 F. Oil a straight sided 12- by 17-inch baking sheet with 1 tablespoon olive oil. Set aside.

Step 2

Heat a medium skillet over medium heat. Add 1 tablespoon of oil along with the garlic and chili paste to the hot pan. Cook, stirring often until fragrant, about 1 minute. Add the spinach and the salt and cook, stirring often to evaporate any excess moisture, for roughly 1 to 2 more minutes. Place the spinach in a medium bowl. Add the ricotta cheese and stir to combine. Set aside.

Step 3

Using a paper towel, wipe out the skillet and bring it back to medium heat. Add the remaining 2 tablespoons of oil to the pan along with the sausage and cook, undisturbed until the sausage is beginning to brown on the first side, about 3 minutes. Using a wooden spoon, break apart the sausage into bite sized pieces. Continue to cook, stirring often and breaking apart as needed, until the sausage is lightly browned, another 5 minutes. Add the onion to the pan and cook until the onion is fragrant and beginning to soften, another 3 minutes. Remove from the heat.

Step 4

Meanwhile, bring a large pot of water to a boil over high heat. Be sure it is a large enough pan to allow the pasta to swim freely. Season generously with salt. Cook the pasta for 4 minutes stirring often to avoid clumping. Drain well, reserving 1/2 cup of pasta water.

Step 5

While the pasta is cooking, add the marinara to the pan with the sausage and onion and mix well. Add the pasta water, pasta, 1 cup mozzarella cheese and 1/2 cup Parmesan cheese to the same pan and stir to combine.

Step 6

Spread the entire mixture on the prepared baking sheet. Dollop the pasta with the ricotta-spinach mixture and sprinkle with remaining mozzarella and Parmesan cheeses. Bake until the pasta is tender, the sauce is bubbly and the top is lightly browned, about 30 minutes. Remove from the oven and let rest for 5 minutes before cutting into squares and serving. Serve with extra warm marinara if desired.