Step 1

Add 2 tablespoons of the butter to the Instant Pot, hit Sauté and Adjust so it's on the More or High setting. Once melted, add the shallot and sauté for 2 minutes until just softened. Add the sausage and garlic and sauté for 3 minutes longer until the sausage is just lightly browned (it should not be fully cooked at all).

Step 2

Add 1 1/2 cups of the marinara sauce, broth and fresh basil leaves. Stir until well combined.

Step 3

Top with the pasta but do not stir. Just smooth it out with a mixing spoon or spatula so it's mostly submerged in the sauce. Top with the remaining 2 tablespoons of the butter cut into pats, the can of stewed tomatoes and baby spinach.

Step 4

Secure the lid, move the valve to the sealing position and hit Cancel followed by Manual or Pressure Cook on High Pressure for 6 minutes. Quick release when done.

Step 5

Add the remaining 2 cups of marinara, heavy cream, Parmesan, Boursin or cream cheese, and fresh oregano. If using the optional spicy ingredients, feel free to add those now as well. Stir until the dairy is fully combined into sauce. Let it rest for about 3 minutes to come together before serving topped with additional Parmesan and oregano, if desired.