These incredible Peanut Butter Bars are packed with peanut butter flavor! A soft and chewy peanut butter blondie topped with peanut butter icing and chopped peanuts. This sweet and salty treat is sure to be a hit!
I typically create my peanut butter desserts with a combination of peanut butter and chocolate (see peanut butter brownies and chocolate peanut butter cookies), but for this recipe I wanted peanut butter to be the star! These have an undeniable peanut flavor in every single bite.
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These peanut butter bars are
- Soft and chewy (just like my maple walnut bars)
- Sweet and salty
- Loaded with peanut butter flavor
- Quick and easy (no mixer required!)
- Versatile: choose from two recipe sizes
Recipe overview
*Full recipe below in recipe card*
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 crunch and saltiness sprinkle roasted salted peanuts right on top of the icing. A sprinkling of flaky sea salt also adds great flavor and texture.
Two size options
9×13: I originally wrote this recipe for a 9×13 pan, which feeds anywhere from 12 to 18.
8×8: I found myself occasionally wanting a smaller recipe so I included the measurements for an 8×8 pan in the recipe card. This size will feed 6-9.
Storage
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.
Best 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.
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Recipe
Peanut Butter Bars
Ingredients
Bars:
- ½ cup unsalted butter, cut into pieces
- 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
Icing:
- 6 tablespoons unsalted butter, cut into pieces
- ½ cup creamy peanut butter*
- ¼ cup milk
- ½ teaspoon pure vanilla extract
- 2 scant cups powdered sugar
- ½ cup roasted salted peanuts, chopped
- Flaky sea salt
Instructions
Bars:
- Preheat oven to 350°F. Line a 9×13 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, microwave butter and peanut butter until melted and smooth. 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.
Icing:
- Once the bars are baked, remove the bars from the oven and place the pan on a wire rack. Immediately proceed with the frosting.
- Place butter, peanut butter, and milk in a saucepan over medium heat. Bring the mixture to a simmer, whisking frequently, 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 flaky sea salt, lightly pressing the peanuts into the frosting. Allow the bars to cool and the frosting to set before cutting and serving.
Video
Notes
- ¼ cup unsalted butter, cut into pieces
- ½ cup creamy peanut butter
- ¾ cup light brown sugar
- 1 large egg
- 1 teaspoon vanilla
- ¾ cup PLUS 2 tablespoons all purpose flour
- ¾ teaspoon baking powder
- ⅛ teaspoon salt
- 3 tablespoons unsalted butter, cut into pieces
- ¼ cup creamy peanut butter
- 2 tablespoons milk
- ¼ teaspoon vanilla extract
- 1 scant cup powdered sugar
- ¼ cup roasted salted peanuts, chopped
- flaky sea salt
Nutrition
Nutritional Information is an estimate based on third-party calculations and may vary based on products used and serving sizes.
Tried this recipe?Leave a comment and rating below!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.
Gloria says
I bet this would be good eating from the fridge. I love cold peanut butter🥰
J Pixler says
This is a perfect peanut butter bar recipe. I make it all the time .
Allison Mattina says
I’m so glad! Thanks for taking the time to comment.
Rhonda Tuzzio says
I had to bake the batter almost twice as long as the recipe directions said. It is cooling on the counter now. The batter and the icing taste good, so I am still hopeful. I think the author needs to reevaluate her baking instructions.
Allison Mattina says
Hi, Rhonda. Sorry to hear that. Perhaps your oven runs cooler than mine. I hope you enjoy them!
Julie says
These bars are fabulous! No other peanut butter bar recipe compares to this. Although I don’t use the icing layer, it is delicious just the way it is with a cookie. Thank you for creating this recipe.
Allison Mattina says
You’re very welcome! Thank you for the kind review. 🙂
Baker Becky says
I loved this recipe, and it was a big hit at the office and at a picnic, but I had made a similar type of bar before, and I figured that with so much butter, foil or parchment paper was not necessary. They popped out of my ceramic baking pan very easily. I also just gradually added the ingredients to butter in the saucepan, instead of getting separate bowls dirty. Again it is a GREAT recipe, but some of the steps are not crucial.
Allison Mattina says
Thanks for sharing your experience. I’m glad you enjoyed them. 🙂
Marci says
These peanut butter bars are always a huge hit at our community Bingo gatherings. I’ve even used the icing recipe to frost peanut butter cookies to elevate them to a heavenly level of yumminess!
Allison Mattina says
Oh! Great idea! I’m glad you enjoyed the recipe. 🙂
Sandra says
I made these today and they are perfect! I took some to my neighbor and she agreed!
I used natural just peanuts peanut butter and these were great!
Allison Mattina says
I’m glad you enjoyed it! Thanks for taking the time to comment. 🙂
Julie says
They are great cold, like peanut butter fudge!
Allison Mattina says
I’m glad you enjoyed them! 🙂
Hollie K Hardin says
First time I’ve tried this, I’ll be saving this recipe Thank you
Allison Mattina says
You’re welcome! Thanks for stopping by. 🙂
MB says
These were quite interesting. The bottom layer was delicious. But together with the icing, they were just too sweet. We love sweet stuff, but these were over the top unfortunately. Next time I’ll just drizzle the icing sparingly on the top. I’m sure they’ll be a lot better.
Allison Mattina says
Thanks for sharing your experience!