Chicken Broccoli Ziti

Bring a large pot of salted water to a boil. Add ziti and cook al dente. In the last 3 minutes, add broccoli and boil for 2-3 minutes. Strain and set aside.
Meanwhile, heat 1 tablespoon of butter over medium heat in a large pan or cast-iron skillet. Add chicken, season with salt and pepper, and fully cook through, about 5-7 minutes. Remove chicken and transfer to a bowl, leaving juices behind. Cover chicken with foil to keep warm.
Melt remaining butter and add onion and garlic to the skillet. Simmer until onions are translucent, about 3-4 minutes. Do not burn. Add chicken broth, cream, and red pepper flakes and bring to a boil. Simmer/boil for about 7 minutes until slightly reduced. Add parmesan cheese and corn starch and stir/whisk until thickened. Start with 1 tablespoon corn starch and add second if you want thicker.
Return pasta and broccoli to the skillet and toss in the sauce. Add chicken and continue to toss until everything is well coated and warm.
Serve with crushed red pepper flakes and additional parmesan cheese!