Bring a large pot of salted water to a boil. Cook the fettuccine until al dente, drain and set aside.
While preparing the pasta, start the chicken. Season the chicken cutlets on both sides with salt, pepper, and garlic powder. Spread the flour on a dinner plate and evenly coat the chicken.
Place a large skillet over medium-high heat. After adding the olive oil to the pan, sauté the chicken until browned on both sides, about 3 minutes per side. Remove from pan and tent with foil.
Add the butter to the pan. Stir in the mushrooms and sprinkle lightly with salt (this will draw out moisture). Sauté until golden brown.
Deglaze the pan with the marsala wine. Simmer until reduced by half, then pour in the cream. Bring back up to a simmer until thickened.
Return the chicken cutlets to the pan and spoon sauce over top. Simmer for 2-3 minutes until they have finished cooking through.
Serve chicken and mushrooms over cooked fettuccine, with sauce ladled over top.
