Bring a large pot of salted water to a boil. Cook the penne pasta according to package instructions until al dente. Add the cubed sweet potato to the pot during the last 5 minutes of cooking. Drain and set aside.

In a large skillet, heat olive oil over medium heat. Add the Italian sausage and cook until browned, breaking it up with a spoon, about 7-10 minutes.

Add minced garlic to the skillet with the sausage and cook for an additional minute until fragrant.

Stir in the heavy cream and bring to a simmer. Allow it to cook for about 3-5 minutes, stirring occasionally.

Add the grated parmesan cheese and mix until melted and smooth. Season with salt and pepper to taste.

Add the cooked pasta and sweet potato to the skillet. Toss everything together until well combined and heated through.

Fold in the fresh spinach and cook until just wilted, about 1-2 minutes.