In a microwave safe bowl combine the butter and peanut butter and cover with plastic wrap. Microwave in 30 second intervals until smooth and combined.
USING THE STOVE TOP
For the stovetop version combine the peanut butter and butter in a medium saucepan on the stove over medium low heat and stir until completely melted and combined.
Add the vanilla to the peanut butter mixture and stir. Add the powdered sugar and peanut butter mixture to a large bowl. Stir together until fully combined.
Spread the fudge into an 8x8" foil or parchment lined pan, smoothing out the top with a spreading knife or the back of a spoon.
Refrigerate 2 hours until completely cool and set, then cut into bite sized squares. Store in an airtight container at room temperature for up to a week.
Notes
Calories are automatically generated. For best results calculate based on your exact ingredients.