Peanut Butter Bars are loaded with peanut butter and topped with peanut butter butterscotch frosting and chopped Reese’s peanut butter cups. Try my Peanut Butter and Jelly Bars for another favorite treat or snack bar!
Peanut Butter Bars
Peanut Butter Bars are soft and chewy bars that are full of peanut butter flavor in every bite! Plus, more peanut butter with butterscotch chips is added to the topping. And, I had to add a hint of chocolate (and more peanut butter) when I added the chopped Reese’s peanut butter cups. So, I can assure you that if you love peanut butter, you will definitely be a fan of these dessert bars. And then you will want to make my Reese’s Peanut Butter Bars.
There are two main parts to this recipe–the bars and the peanut butter topping. The bars are delicious on their own but don’t skimp on the topping if you want even more peanut butter flavor. (Plus, the topping is also delicious on ice cream!)
Room Temperature Ingredients: Using room temperature ingredients (specifically eggs in this case) will help you get the best results when baking these bars.
Peanut Butter: I used creamy peanut butter for the bars and chunky peanut butter for the topping. You could use all creamy or even all chunky if that is what you have on hand.
Eggs: You will need two whole eggs and one additional egg yolk. Be sure to add each egg one at a time before adding another one; this ensures the egg will emulsify with the butter.
Cornstarch: Adding cornstarch to the batter will give the bars a soft texture.
Butterscotch: I added some butterscotch chips to the peanut butter topping for even more flavor.
Reese’s Peanut Butter Cups: Chop up about a cup of mini Reese’s peanut butter cups to add to the top of the bars for the final touch and a little chocolate.
How to Make Peanut Butter Bars
As I stated above, these bars are tasty enough to stand on their own. They are made in an 11×15-inch sheet pan, which I cut into 15 bars. To make the batter, first, combine the melted butter and brown sugar. Stir well and then mix in the peanut butter. One at a time, add the eggs. Again, adding and mixing eggs one at a time will give the eggs time to be fully incorporated with the butter mixture. Adding them all at once will disrupt the nice suspension you will get from adding them one at a time.
After you have added the eggs and egg yolk, stir in the vanilla. In a separate bowl, whisk together the dry ingredients and slowly add them to the butter and egg mixture. Spread the batter out evenly into the sheet pan (jelly roll pan), and gently press it down to create an even layer. You could use a piece of parchment paper to press down on the batter if that helps.
Bake the bars for 15-20 minutes, or until the edges just begin to turn golden brown. When the bars are done baking, remove them from the oven and let them cool completely before adding the peanut butter topping. Maybe cut off a corner to taste how delicious the bars are on their own!
How to Make the Topping
Once the bars have cooled, get out a saucepan to make the peanut butter topping. To make the topping, melt the butter and peanut butter over medium-low heat. After those ingredients have melted, add the butterscotch chips. Remove the pan from the heat and stir until the chips are mostly melted. This is the same recipe I used on my Peanut Butter Cookie Brownies.
Pour the topping over the cooled bars. Finally, sprinkle some chopped Reese’s peanut butter cups over the top and place the pan in the refrigerator for a few minutes to let the topping set. After 3-5 minutes, the bars should be ready to cut and enjoy!
Can I Make these Bars in a Different Size Pan?
Yes! If you don’t have an 11×15-inch sheet pan (or jelly roll pan), you can make these in a 9×13-inch baking dish or even a 9x9x2-inch dish. However, just be aware that the baking times will be different since the bars will be thicker. As for the sauce, you shouldn’t have too much leftover, if any, depending on how thick you pour it on.
Looking for More Peanut Butter Desserts?
Peanut Butter Bars are loaded with peanut butter and topped with peanut butter butterscotch frosting and chopped Reese's peanut butter cups.
- ¾ cup (1½ sticks, 170g) unsalted butter, melted
- 1¾ cups (350g) light brown sugar, packed
- ¾ cup (193.5g) creamy peanut butter
- 2 large eggs + 1 egg yolk, room temperature
- 1½ teaspoons vanilla extract
- 2½ cups (285g) all-purpose flour
- 2 teaspoons cornstarch
- 1 teaspoon baking powder
- 1 teaspoon kosher salt
- ½ cup (1 stick, 113g) unsalted butter
- ½ cup (129g) chunky peanut butter
- ½ cup (85g) butterscotch chips
- 1 cup miniature Reese's peanut butter cups, roughly chopped
Preheat the oven to 350°F and line an 11x15-inch sheet pan with parchment paper (or lightly grease and flour).
In a large bowl, combine the melted butter and brown sugar. Stir well.
Add peanut butter and mix until creamy.
Add the eggs and the egg yolk, one at a time, stirring well after each addition.
Stir in the vanilla extract.
In a separate, medium-sized bowl, whisk together the flour, cornstarch, baking powder, and salt.
Gradually stir the flour mixture into the butter and egg mixture until completely combined.
Spread the batter evenly into the prepared pan. Firmly press the batter into the pan into a flat, even layer. (We used another piece of parchment to press down on the batter.)
Bake for 15-20 minutes, or until the edges just begin to turn golden brown.
Allow the bars to cool completely before adding the peanut butter sauce.
In a medium saucepan, melt butter and peanut butter over medium-low heat. Once they are fully melted and combined, add in butterscotch chips. Remove from heat and stir continually until mostly melted. (There will be chunks in the bottom of the pan, but this is okay.) Set aside to cool slightly.
Pour the sauce over the cooled bars, spreading it with a spatula if needed.
Top with chopped Reese's peanut butter cups.
Set the pan of bars in the refrigerator to allow the peanut butter topping to set (3-5 minutes) before cutting and enjoying.