Heat the clarified margarine (or butter or olive oil) in a skillet over medium heat. Sautee the chicken breasts for about eight minutes and remove from the pan.
Add the garlic and saute for a few seconds. Add the white wine. Allow most of the wine to boil away, then add the cream. Bring to a light boil, and reduce by about half.
In the meantime, in a separate skillet, sautee the mushrooms in the butter until they soften. Add the white wine and cook until most of the liquid is evaporated. Remove from the heat and keep warm.
Return the chicken to the pan with the creamy bordelaise sauce, and cook until the chicken is completely done. Place the chicken breasts on the plate and keep warm.
Bring the sauce up to a good simmer again. Chip the butter into the sauce and whisk it in. Nap the sauce over the chicken breasts. Top with some of the mushrooms. Serve with vegetables and potatoes, rice, or pasta.