Okay i make a double batch each time as it's easier due to the fact the smaller jars of PB are 2 cups already

and the powdered sugar comes in a 2 lbs package also.
EASY PEANUT BUTTER FUDGE
2 sticks butter
1 cup creamy peanut butter
1 tsp. vanilla
1 lb. powdered sugar
Melt the butter and peanut butter (you may use microwave). Stir in vanilla. Beat in powdered sugar. Quickly spread into a buttered 8x8-inch square buttered dish. Chill to set. Cut into 64 squares.