In a medium microwave safe bowl, add semi sweet chocolate chips and ¼ cup of peanut butter. Place in the microwave and cook for 30 seconds. Remove and stir; will be partially melted. Place back in the microwave and cook 15 seconds, remove and stir. Continue cooking in 15 seconds increments until completely melted.

Using a second microwave safe bowl, add the white chocolate chips and the remaining peanut butter. Repeat the melting process and set aside.

Using a medium baking dish (square 8x8 or similar rectangle shape is perfect) lined with parchment paper, pour the semi sweet chocolate mixture into the dish, then spread to distribute evenly. Then, carefully pour the white chocolate mixture over the top.

Using a butter knife or skewer, place it down into the fudge, then run it in lines throughout the fudge (this will slightly swirl the layers).

Place in the fridge for at least 8 hours to set.

Remove and cut the peanut butter fudge into squares.