Step 1

Generously season a large pot of water & bring to a boil. Add the rigatoni & cook, stirring occasionally, until the pasta is 2-3 minutes under al dente (“al dente” cooking time is typically included in package directions). Drain the pasta – do not rinse! – & set aside. (Learn more ⇢ How to Cook Pasta Perfectly Every Single Time!)

Step 2

Add the olive oil to a large skillet over medium-high heat. Once the oil is hot & shimmering, add the bell pepper & onion, seasoning with 1 teaspoon kosher salt. Cook, stirring occasionally, until softened & fragrant, 4-5 minutes. Add the sausage to the skillet. Let it brown for 2-3 minutes, then use a wooden spoon to break it apart into fine crumbles. Continue to cook & crumble until the sausage is nicely browned & rendered, 2-3 minutes more. Stir to combine with the softened veggies.

Step 3

Push the sausage & veggies to the side of the skillet & add the garlic, Italian seasoning, fennel seeds, & crushed red pepper flakes (if using) to the skillet such that everything comes into contact with the hot surface of the skillet. Cooking until just fragrant, about 30 seconds to 1 minute.

Step 4

Stir the tomato paste into the skillet, stirring to coat the sausage & veggies. Cook for 2-3 minutes, until deeply red. Deglaze the pan by slowly pouring in the white wine, using a wooden spoon to scrape up any browned bits that may have formed on the bottom of the pan. Once the wine is almost completely cooked off, add in the crushed tomatoes, diced tomatoes (& their juices), spinach, & 1/2 cup grated parmesan cheese. Stir to combine & wilt the spinach. Bring the mixture up to a simmer, then reduce heat to medium-low. Let the sauce simmer for 5 minutes, stirring occasionally, to thicken slightly & build flavor. Taste & adjust seasoning accordingly, then remove from the heat.

Step 5

Preheat the oven to 400 degrees F, ensuring a rack is positioned in the upper third of the oven. Lightly spritz a large piece of foil & a 9×13 pan with nonstick cooking spray. Set aside. Add the rigatoni to the prepared tomato sauce, tossing well to ensure all of the pasta is coated. Transfer half of the pasta & sauce to the prepared baking dish. Dot 1/2 of the ricotta over the surface of the pasta, then sprinkle 1/2 of the shredded mozzarella cheese over top. Repeat by building one more layer – pasta & sauce, ricotta, mozzarella. Finish by sprinkling the remaining 1/2 cup grated parmesan over top.

Step 6

Place the pan on top of a baking sheet then cover with the prepared foil. Once the oven is preheated, transfer to the oven & bake 25 minutes, until the baked rigatoni is bubbling & the cheese is melted. Carefully remove the foil & turn the oven’s broiler on high. Broil the baked rigatoni about 5 minutes, keeping a close eye on it as it broils to make sure it doesn’t burn, until it’s as bubbly & golden brown as you like.

Step 7

Carefully remove the baked rigatoni from the oven. Allow to cool slightly, then serve topped with additional grated parmesan or finely chopped fresh herbs as desired. Enjoy!