Split each chicken breast through the middle to make 2 pieces. Place plastic wrap over them and pound each one flat. Season a good amount of salt and pepper on both sides of each piece.
Heat 1 tbs butter over medium heat and brown the chicken but do not cook all the way through. Remove chicken and set aside.
Add 1 tbs butter, garlic, and mushrooms to the pan. Saute mushrooms for 4-5 minutes making sure to season them with salt and pepper lightly. Add marsala wine and bring to a boil. When reduced by half, add cream and chicken stock allowing the liquid to reduce slightly – approx. 3 minutes.
Return chicken to the pan and simmer until chicken is done. Stir in remaining two tbs of butter and top with parsley and oregano or chives.