Microwave butter and peanut butter for 2 minutes on high. Stir and microwave on high for 2 more minutes.

Add vanilla and powdered sugar to peanut butter mixture and stir to combine with a wooden spoon.

Pour into a buttered 8X8 inch pan lined with waxed paper.

Place a second piece of waxed paper on the surface of the fudge and refrigerate until cool.

Cut into 1-inch pieces and store in an airtight container for up to a week.