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 and cook for an additional 1-2 minutes until fragrant.
Stir in the cherry tomatoes and spinach, cooking until the spinach wilts, about 2-3 minutes.
Pour in the heavy cream and stir to combine. Bring to a gentle simmer.
Add the cooked penne pasta to the skillet, along with the grated Parmesan cheese and Italian seasoning. Stir until the pasta is well coated and the sauce is creamy. Season with salt and pepper to taste.
Remove from heat and let it sit for a couple of minutes to thicken slightly.
Serve warm, garnished with fresh basil if desired.