Bring a large pot of salted water to a rolling boil. Add tortellini and cook according to package directions until al dente. Reserve 1/2 cup pasta water, then drain.

While pasta cooks, melt butter in a large skillet over medium heat. Add minced garlic and cook 30–45 seconds until fragrant. Don't brown the garlic.

Pour in the heavy cream and bring to a gentle simmer. Let it reduce for 2–3 minutes, stirring frequently.

Stir in the Parmesan cheese until melted and smooth. If the sauce is too thick, add a splash of reserved pasta water to loosen. Taste and season with salt and pepper.

Add shredded rotisserie chicken to the sauce to warm through (about 1–2 minutes).

Toss drained tortellini into the skillet, coating each piece in sauce. Heat together for 1–2 minutes so flavors meld.

Serve immediately, garnished with chopped parsley and extra Parmesan if desired.