Soft and chewy Peanut Butter Bars topped with peanut butter icing and chopped peanuts. This sweet and salty treat is loaded with delicious peanut butter flavor.
Gather ‘round peanut butter lovers – these are for you! Soft and chewy, sweet and salty Peanut Butter Bars with Peanut Butter Frosting! These bars should come with a warning. Something along the lines of, “do not leave yourself alone in the house with these,” “prepare to exhibit little-to-no self control,” “find some friends to share these with” … because, dang it, they are SO GOOD.
I set out to create a Peanut Butter Bar that was loaded with peanut butter flavor. Peanut butter desserts can often be lacking in the flavor department, but I wanted to make sure these had undeniable peanut flavor in every bite. Mission accomplished!
Peanut Butter Bars with Peanut Butter Frosting
These bars are made up of three different components: base, icing, and topping.
Peanut Butter Blondie: The base of these bars is a combination of a blondie and a soft cookie. Peanut butter, melted butter, brown sugar, and vanilla flavor the bars and makes them soft and chewy.
Peanut Butter Icing: This icing comes together quickly on the stovetop. A combination of butter, peanut butter, and milk is heated in a saucepan. Powdered sugar and vanilla are whisked in, then the icing is quickly added to the warm bars and spread into an even layer. This icing will firm up as it cools.
Toppings: In order to add some crunch and a slight saltiness, I sprinkle roasted salted peanuts right on top of the icing. I also like adding a sprinkling of flaky sea salt to bump up the saltiness even more (optional).
How to Store Peanut Butter Bars:
These bars need to cool completely before cutting. Once cool, you can store them tightly-covered at room temperature for several days. I find that they are best within 2 days of baking.
These bars can also be frozen. I thaw them in the refrigerator, then bring to room temperature. You can also reheat them individually in the microwave. Note: the warmer they get, the softer the icing will become.
Proper Peanut Butter for Baking:
When baking with peanut butter, it is almost always best 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.
All-natural peanut butter (only ground peanuts) separates and might not mix into the blondie base or the frosting as well as a fully combined peanut butter. Although I prefer natural peanut butter for snacking and sandwiches, I highly recommend that you go with an emulsified peanut butter for baking.
Peanut Butter Bars
- ½ cup unsalted butter, melted
- 1 cup creamy peanut butter* at room temperature, see note
- 1 ½ cups light brown sugar, make sure it is fresh and soft
- 2 large eggs
- 2 teaspoons pure vanilla extract
- 1 ¾ cups all purpose flour
- 1 ½ teaspoons baking powder
- ¼ teaspoon salt
- 6 tablespoons unsalted butter, cut into pieces
- ½ cup creamy peanut butter*
- ¼ cup milk
- ½ teaspoon pure vanilla extract
- 2 cups powdered sugar
- ½ cup roasted salted peanuts, chopped
- 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.
Note: This recipe was originally made with maple flavored peanut butter. Feel free to use that in place of regular peanut butter, if you prefer.