1cupcreamy peanut butter* at room temperaturesee note
1 ½cupslight brown sugarmake sure it is fresh and soft
2teaspoonspure vanilla extract
1 ¾cupsall purpose flour
1 ½teaspoonsbaking powder
6tablespoonsunsalted buttercut into pieces
½cupcreamy peanut butter*
½teaspoonpure vanilla extract
½cuproasted salted peanutschopped
Flaky sea salt
Preheat oven to 350°F. Line a 9x13 pan with foil or parchment paper, leaving overhang on at two sides for easy removal. Grease the foil or parchment, set aside.
In a large bowl, whisk butter and peanut butter until combined. Add brown sugar, whisking until combined. Add eggs and vanilla, whisk until combined, stopping to scrape the sides of the bowl as needed.
In a separate bowl, combine flour, baking powder, and salt. Add flour mixture to the wet ingredients and stir with a rubber spatula until combined. Stir just until no streaks of flour remain, and be careful not to overmix. The batter will be thick.
Transfer the batter to the prepared pan and press it into an even layer. Bake for 17-20 minutes, until light golden brown. During bake time, place the butter, peanut butter and milk (for the icing) in a saucepan. Set it aside (uncooked) until the bars comes out of the oven. Once baked, remove the bars from the oven and place the pan on a wire rack. Immediately proceed with the frosting.
Place the saucepan (with butter, peanut butter and milk) over medium heat. Whisking frequently, bring the mixture to a simmer, then remove from the heat. Immediately whisk in vanilla extract and powdered sugar, whisking until smooth and combined. Pour over the warm bars and spread into an even layer. Work quickly; this frosting will firm up fast. Sprinkle with peanuts and flaked sea salt (if using), lightly pressing the peanuts into the frosting. Allow the bars to cool and the frosting to set before cutting and serving.
*Peanut Butter: Be sure to use a traditional, no-stir, emulsified peanut butter. This is the typical commercial brand peanut butters that are thoroughly combined straight off the shelf, and do NOT have a thick layer of oil on top.