Preheat oven to 400 degrees. Either pound the chicken breast to an even thickness or cut in half with a knife. this will help the meat to cook more evenly. Rub the chicken breast with drops of lemon juice and sprinkle lightly with salt & pepper.
Heat the butter in a heavy, fry pan , about 10 inches in diameter until it is foaming.Stir in the minced shallots a sauté a moment without browning.Stir in the mushrooms and sauté lightly for a minute or two without browning. Sprinkle with salt.
Quickly roll the chicken in the butter mixture cooking for only a few minutes on each side, just enough to brown the chicken. Remove chicken to casserole dish, leaving the mushrooms in the pan. Lay a piece of buttered wax paper over the chicken pieces, once all of the chicken pieces have been put into the casserole dish place in hot oven, leaving the wax paper on. After 6 minutes, press top of chicken with your finger. If still soft, return to oven for a moment or two.When the meat is springy to the touch it is done. Remove the chicken to a warm platter.
To make sauce, pour the stock and wine in the fry pan with the remaining butter and mushrooms.Boil down quickly over high heat until liquid is syrupy.Stir in the cream and boil down again over med heat until cream is thickened slightly.
Remove from the heat, taste for seasoning and add drops of lemon juice to taste. Pour the sauce over the chicken, sprinkle with parsley and serve immediately.