Step 1

Line an 8x8-inch pan with parchment paper, leaving some hanging over the sides of the pan slightly for easy fudge removal later.

Step 2

Add the creamy peanut butter to a microwave-safe bowl and heat it in the microwave for 30 seconds. Stir well and microwave for another 15-30 seconds. It will become even creamier and very easy to stir.

Step 3

Remove the peanut butter from the microwave and fold in the vanilla frosting thoroughly until evenly combined. It will thicken the more you stir, but shouldn't be too firm.

Step 4

Transfer the combined peanut butter fudge mixture into the prepared baking pan. Use a rubber spatula or the back of a knife to smooth the fudge into the corners of the pan and create a smooth top.

Step 5

If desired, sprinkle sea salt on top of the fudge. Place in the fridge to set up for 2 hours. After chilling, remove the fudge by running a knife around the edges of the pan and lifting the fudge out by the edges of the parchment paper.

Step 6

Slice the fudge into squares and enjoy immediately. Store leftover fudge in an airtight container in the fridge or freeze as desired (see notes).