In a nonstick pan, melt 2 tablespoons of butter. Put in whole mushrooms and saute until browned – about 5 minutes [on med-high heat]. Add in 1/2 cup fresh mozzarella, 2 tablespoons sour cream and 1 teaspoon sage plus some salt and pepper. Bring to a temperature allowing the cheese melt. Stir in a figure 8 to mix ingredients thoroughly. Serve hot.