Step 1

In an 8" x 8" or 9" x 9" square pan, make a sling out of parchment paper, with two sides hanging over the edge of the pan. Lightly grease the paper and sides of the pan.

Step 2

If using graham cracker crumbs instead of the chocolate topping, sprinkle half of the crumbs over the bottom of the greased pan. Skip this step if making with chocolate.

Step 3

In a large bowl, combine peanut butter, butter, and vanilla extract with an electric mixer.

Step 4

Slowly add in powdered sugar one cup at a time until the mixture resembles a dough and is no longer sticky. For me, this was at about 5-1/4 cups.

Step 5

Pat the mixture into the prepared pan and then top with remaining graham cracker crumbs. Alternatively, melt the chocolate chips in a microwave in 30 second intervals, stirring between each, until melted. Spread evenly over the peanut butter mixture.

Step 6

Refrigerate until chilled.**

Step 7

Carefully remove the bar, by lifting directly up on the parchment paper wings. Cut into squares and enjoy!