Cook the Pasta - Bring a large pot of salted water to a boil. Add the rigatoni and cook according to package directions until al dente. Drain and keep warm.

Cook the Chicken - While the pasta is cooking, sauté onion and garlic in the oil over medium heat until softened. Watch carefully to not burn! Add chicken and cook until no longer pink, about 8-10 minutes.

Add the Veggies - Stir in the tomatoes, basil, peppers, and mushrooms. Bring to a simmer, reduce heat and continue to simmer until peppers are softened. Add salt and pepper to taste.

Make the Sauce - While the chicken and pepper combination simmers, melt butter in a small saucepan over medium-low heat. Stir in flour until a paste forms. Add the milk, stirring until heated through. Add the parmesan, stirring constantly until a thick sauce forms. Be patient and keep stirring.

Finish and Serve - To serve, you may combine the pasta and the finished sauce all together or you may individually serve the pasta topped with the sauce. Sprinkle more parmesan and add more cherry peppers to taste.