2tablespoonsvegetable shorteningoptional but recommended so chocolate doesn’t set up overly firm and crack upon slicing
Instructions
Preheat oven to 350F. Line an 8-inch square baking pan with aluminum foil and spray with cooking spray; set aside.
Shortbread Crust
Combine all ingredients in a large bowl, cutting in the butter with a pastry cutter or two forks until until a sandy, crumbly mixture forms.
Turn crumbly mixture out into prepared pan and using your fingertips or a spatula, hard-pack the crumbs to form an even, flat, smooth crust layer. Pierce crust with a fork in a dozen places so steam can escape while it bakes.
Bake for 12 to 13 minutes, or until crust has just barely set. It should not be golden or browned and should still be white, but crusted over and set. While crust bakes, make the filling.
Peanut Butter Filling
Add the butter to a medium microwave-safe bowl and heat on high power to melt, about 1 minute. Add the remaining ingredients and stir until smooth.
Spread filling over crust using a spatula, knife, or offset knife. Crust does not have to be cool, and spreading filling while crust is still warm is beneficial to help it smooth out more easily; set aside.
Chocolate Layer
Add the ingredients to a medium microwave-safe bowl and heat on high power to melt, about 1 minute. Stop to check and stir, and heat in 15-second bursts until mixture can be stirred smooth.
Pour chocolate over peanut butter and shake the pan a bit to help chocolate slide and disperse. Then smooth it very lightly with an offset spatula, knife, or offset knife.
Cover pan with a sheet of foil and allow bars to cool and set up for at least 4 hours, or overnight, before slicing and serving.
Alternatively, place pan in the refrigerator for at least 3 hours to help expedite the cooling process, noting that sometimes chocolate becomes a bit dull-looking (cosmetic only and doesn’t effect taste) if refrigerated. If bars have become very cold, allow them to come up to room temperature for a few minutes before slicing so neither crust nor chocolate cracks.
Notes
Bars will keep airtight at room temp for up to 1 week.