1. Flatten breasts of chicken with the back of a sauté pan between wax paper if you didn’t cut them thin enough (1/4 inch or so). Pat them in the flour mixture and set aside.
2. Heat the sauté pan to medium/high and add the oil and 1/2 the butter. When back up to heat and butter is melted, add the chicken. (If the butter starts boiling it will burn so lower the heat until you put the chicken in.) When the edges of the first side start to appear cooked, turn them over. Add a splash of lemon and wine, salt and pepper to taste, and cook until done. When done, set aside and keep warm. You may have to do this a few times depending on the size of your pan or how much you are making.
3. De-glaze the pan over hot heat with the wine to dissolve the brown particles and let it reduce. Note: If you are using gas and tip the edge of the pan over the flame it will ignite ( flambe ) and flame up to burn off the alcohol – BE CAREFUL! Then add the stock, butter, and lemon juice and let reduce further. Add a pinch of flour to thicken or use 1/2 teaspoon of Roux (below). This should take about a minute or so. When thickened, add mushrooms, garlic, parsley, and the sliced lemon to the pan and sauté for a minute or so and blend well. Place the chicken a serving platter or plates, spoon over juices, top with lemon slices and serve immediately.

Roux

1. This is the best thickening agent and can be used in anything – demi-glazes, gravies, soups, etc.
2. Use equal parts butter and flour.
3. Melt butter; slowly whisk in flour and simmer until golden brown and remove from flame. DONE! When using a roux it must be at room temperature or cooler than the product being cooked. Over medium heat, stir in a little roux until dissolved and let thicken. Start off with a teaspoon per quart of liquid, or fraction thereof, and add as required.

Buona Appetito, VINCENZO