Fill a large pot with salted water and bring it to a boil. Add the fresh or frozen tortellini and cook according to the package instructions, usually about 3 to 5 minutes for fresh and 5 to 7 minutes for frozen. They’re done when they float to the surface and are tender but still have a slight bite. Drain the tortellini, reserving about 1/4 cup of the pasta water for later.
While the pasta cooks, toss the fresh basil leaves, pine nuts, grated Parmesan, garlic cloves, and a pinch of salt into your food processor or blender. Pulse a few times to chop everything up. Then, slowly drizzle in the olive oil while blending until you reach a smooth, vibrant green pesto. Taste and adjust salt and pepper as needed.
In a large skillet over medium heat, pour in the heavy cream and warm it gently for about 1-2 minutes until it’s just starting to simmer. Stir in the pesto, mixing well to create a creamy, fragrant sauce. If the sauce feels too thick, stir in a splash of the reserved pasta water to loosen it up to your desired consistency.
Add the drained tortellini to the skillet, tossing gently to coat each piece in the creamy pesto sauce. Allow everything to warm through for another minute or two. If you’re adding grilled chicken or turkey, now’s the time to fold it in so the flavors meld beautifully.
Dish out the creamy pesto tortellini onto plates or bowls. Garnish with halved cherry tomatoes for a burst of freshness and a sprinkle of extra Parmesan if you like. Serve immediately and enjoy!