Place chocolate and peanut butter in a microwave-safe bowl and cover. Melt chocolate and peanut butter in microwave for a minimum of 1 1/2 minutes on high. Stir well and microwave another 20 seconds or until the mixture is melted and smooth when stirred. Add butter/milk mixture to peanut butter/chocolate and stir well with electric mixer or by hand. Stir in remaining 1 tsp. vanilla extract.
Foil line an 8" square pan and pour fudge into it. Flatten top with knife or wooden spoon. Cover and refrigerate for about 1 hour. Cut into squares. Keep refrigerated. Stays fresh for about 3 to 4 days in fridge or in freezer in an airtight container for up to 2 months.
Nutrition Facts/Serving: 1 square
** This stevia amount is the minimum to use in the recipes.