Slice chicken breast into pieces, the size of your choice. I sliced them into three pieces.
In a plate, season flour with salt and pepper, stir to combine. Heat the skillet with the olive oil over medium high heat.
Flour each side of chicken breast with flour. Cook chicken on each side until golden brown.
Cut mushrooms into small pieces and set aside. Dice onions into small cubes.
Reuse the same skillet to maintain the flavor, cook mushrooms until they are browned. Add onion into cooking mushrooms, cook until onions are soft. Remove cooked ingredients form the skillet, set aside.
To the same skillet, add Marsala wine and cook for a minute, until the volume reduces. Stir whipping cream into the wine and bring it to a boil. To the sauce, add mushroom & onion mixture.
Top chicken with mushroom Marsala sauce and serve hot.