Cook the penne pasta according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the Italian sausage and cook until browned, breaking it apart with a spoon, about 5-7 minutes.
Add the minced garlic to the skillet and sauté for 1 minute until fragrant.
Stir in the cherry tomatoes and cook for another 2-3 minutes until they start to soften.
Add the fresh spinach and cook until wilted, about 2 minutes.
Pour in the heavy cream and stir to combine. Bring to a gentle simmer.
Mix in the grated Parmesan cheese and Italian seasoning, stirring until the cheese is melted and the sauce is creamy. Season with salt and pepper to taste.
Add the cooked penne pasta to the skillet and toss to coat the pasta in the sauce.
Serve immediately, garnished with fresh basil if desired.