Heat olive oil in a large pot or deep skillet over medium heat. Add minced garlic and cook for 1 minute until fragrant.
Add the sun-dried tomatoes and red pepper flakes (if using), stirring for another minute.
Pour in the vegetable broth and bring to a boil. Add the penne pasta, stirring to ensure it's submerged.
Reduce heat to medium and cook for 12-15 minutes, stirring occasionally, until pasta is almost al dente and most liquid is absorbed.
Stir in the heavy cream, spinach, and Parmesan cheese. Cook for 2-3 more minutes until spinach wilts and sauce thickens.
Season with salt and pepper to taste, garnish with fresh basil, and serve immediately.