Cook the pasta according to the package directions, drain and set aside.
Melt the butter in a large sauté pan. Stir in the peppers, onion, and mushrooms. Cook until tender and onions are slightly translucent, about 3 to 5 minutes.
Stir in the garlic, red pepper flakes, Cajun seasoning, salt, and pepper. Cook one minute longer.
Stir in the cream and chicken broth. Bring to a simmer.
Stir together the cornstarch and hot water until dissolved. Add to your sauce and cook until slightly thickened.
Remove from the heat and stir in the parmesan and chicken.
Serve immediately.
Notes
Substitute shrimp for chicken to give this a fun twist!