Slice chicken on an angle into 3/4 inch pieces; season generously with salt and pepper.
In a 10 inch straight sided saute pan, heat 2 TBL of oil over medium high heat; saute half of the chicken turning once until lightly browned and barely cooked through- about 1-2 minutes per side; Transfer cooked chicken to a plate and cover with foil to keep warm; repeat with remaining chicken.
Return pan to medium high heat and add remaining 1 TBL oil.
Add mushrooms, season and saute stirring with a wooden spoon until softened and well browned- 3-4 minutes.
Reduce heat to medium, add garlic and cook stirring for 30 seconds.
Add Marsala and scrape pan to loosen brown bits; simmer until slightly reduced- about 2 minutes.
Stir in cream and simmer until thickened slightly- 2-3 minutes.
Add 2/3 of the gorgonzola and stir until melted- 1-2 minutes.
Taste sauce and adjust seasoning.
Add chicken along with any accumulated juices and turn to coat with sauce.
Serve immediately, sprinkled with remaining cheese and parsley.