1. Bring a large pot of salted water to a boil and cook the tortellini according to package instructions.

2. Reserve 1/4 cup of the pasta water, then drain the tortellini.

3. Melt butter in a medium skillet over medium heat and sauté minced garlic until fragrant.

4. Pour in heavy cream and heat until it begins to thicken.

5. Stir in the pesto and reduce heat to low.

6. Add the drained tortellini to the skillet and toss to coat in the sauce.

7. Add reserved pasta water as needed to achieve desired sauce consistency.

8. Sprinkle grated Parmesan cheese over the pasta and stir until melted.

9. Season with salt and black pepper to taste.

10. Fold in optional add-ins like spinach or sun-dried tomatoes if desired and serve immediately.