Cook the cheese tortellini according to package instructions. Drain and set aside.
In a large skillet, heat the olive oil over medium heat. Add the minced garlic and sauté for about 1 minute until fragrant.
Add the fresh spinach to the skillet and cook until wilted, about 2-3 minutes.
Pour in the heavy cream and stir to combine. Bring the mixture to a gentle simmer.
Stir in the grated Parmesan cheese, salt, black pepper, and red pepper flakes (if using). Mix until the cheese is melted and the sauce is creamy.
Add the cooked tortellini to the skillet and gently toss to coat the pasta in the creamy sauce.
Cook for an additional 2-3 minutes to heat everything through.
Serve immediately, garnished with fresh basil if desired.