- Cook pasta according to package directions; drain and set aside. 
- Slice chicken breasts thin and season with garlic powder, salt, and pepper. 
- Dredge chicken pieces in flour, shaking off excess. 
- Heat olive oil and 1 tablespoon butter in a large skillet over medium-high heat. 
- Sauté chicken until golden brown on both sides and cooked through; remove and set aside. 
- Add mushrooms to the same pan and cook until tender and golden. 
- Pour in Marsala wine and let reduce by half, scraping up any browned bits. 
- Add chicken broth and Dijon mustard; simmer for 2-3 minutes. 
- Stir in heavy cream and remaining butter; simmer until sauce thickens slightly. 
- Return chicken to the pan and coat with sauce. 
- Toss chicken and sauce with cooked pasta. 
- Serve immediately with Parmesan cheese if desired.