Bring a large pot of salted water to a boil over high heat. Add the penne pasta and cook according to package instructions until al dente, about 8-10 minutes. Reserve 1 cup of pasta water, drain the rest, and set aside.

In a large skillet, heat 2 tablespoons of olive oil over medium heat. Add the Italian sausage, breaking it into small pieces. Sauté until golden brown, about 5-7 minutes. Remove sausage and set aside, leaving drippings.

Lower heat to medium-low and add minced garlic to the skillet. Sauté for about 1 minute until fragrant. Stir in sun-dried tomatoes, chicken broth, Italian seasoning, and red pepper flakes. Simmer for 3-5 minutes.

Pour in heavy cream and add grated Parmesan cheese, stirring until smooth. Add the browned sausage and baby spinach. Cook for 1-2 minutes until spinach wilts and sauce is velvety. Season with salt and pepper.

Add cooked penne pasta to the skillet, tossing gently to coat with the sauce. If too thick, add reserved pasta water gradually to achieve the desired consistency.

Transfer to serving plates, garnish with fresh basil and additional Parmesan cheese. Serve immediately.