Bring a pot of salted water to a boil. Add tortellini and cook according to package directions (usually ~3–5 minutes). Reserve 1/4 cup of the pasta water. Drain the rest of the water and set pasta and reserved 1/4 cup of water aside.

In a large skillet, heat olive oil over medium heat. Add garlic and sauté for 30 seconds until fragrant. Add kale and cook for 2–3 minutes until wilted.

Lower the heat, add heavy cream, pesto and pasta water to the skillet. Stir until combined and slightly thickened (about 2 minutes).

Add the cooked tortellini and Parmesan to the skillet. Toss gently until coated in the sauce. Season with salt, pepper, and optional red pepper flakes.

Plate and top with extra Parmesan, lemon zest (optional) or toasted pine nuts for added flavor and crunch.