Wash mushrooms in hot water. Dry off with a paper towel and slice the mushrooms. In a large skillet over medium heat melt the butter, then add the mushrooms. Season with salt and black pepper. Saute until the mushrooms have browned. Sprinkle flour over the mushrooms and then cook the mushrooms for a minute or two.
Add wine, and stir, the sauce will thicken.
If you have never used beef base before it is sold right next to soups, stocks, and bouillon in the grocery store. Bouillon is concentrated paste that is ideal for making soups, gravies, and anytime you need a boost of flavor.