Peanut Butter Bars

Published June 1, 2019. Updated August 26, 2019

This post may contain affiliate links. Read our disclosure policy.

Peanut Butter Bars are one of the best treats! You get a chewy oat cookie base that’s loaded with peanut buttery flavor, then it’s topped with a layer of peanut butter after baking and finished with a decadent chocolate frosting. Trust me this is a staple recipe!

Stack of peanut butter bars.

The Best Peanut Butter Bars!

These are one of my favorite all time favorite childhood treats. My mom and everyone else I know always made them. They’re just one of those old fashioned classics!

They are perfect for parties because they make a full cookie sheet, and adults and children alike absolutely love them.

I mean, who doesn’t love the chocolate and peanut butter combo, and who doesn’t love cookie bars and frosting?

I made them yesterday and it’s one of those things where I kept going back and cutting off a thin slice, then another, then another and then I woke up for breakfast at it was the first thing I just had to have a taste of.

They really are one of the most tempting desserts you’ll ever make! Try them and you’ll see what I mean.

Peanut Butter Bar dough in a mixing bowl.

Peanut Butter Bar Ingredients:

  • All-purpose flour – for structure
  • Quick oats – for texture
  • Baking soda – so the bars rise
  • Brown sugar, granulated sugar and powdered sugar – to sweeten
  • Salt – to balance the sweetness
  • Unsalted butter – to moisten and add richness
  • Eggs – to bind
  • Creamy peanut butter – to add flavor
  • Vanilla – to add another light layer of flavor
  • Cocoa powder – to add chocolate flavor to the frosting
  • Milk – to thin the frosting

Peanut butter bars on a baking sheet before baking.

How to Make Peanut Butter Bars:

Even though these have several layers these really are a breeze to make.

  • Preheat oven and butter a rimmed baking sheet.
  • Whisk together dry ingredients.
  • In an electric mixer cream together butter, brown sugar and granulated sugar
  • Mix in eggs one a time then blend in peanut butter and vanilla.
  • Mix in dry ingredients.
  • Spread mixture onto baking sheet.
  • Bake until nearly set.

Dollops of peanut butter melting on warm peanut butter bars after baking.

  • Cool briefly then dollop over peanut butter, let peanut butter melt then spread.

Spreading peanut butter over warm peanut butter bars.

  • Prepare chocolate frosting then pour over peanut butter layer and spread even. Let set.

Adding chocolate frosting to peanut butter bars.

Tips for this Recipe

  • Don’t use crunchy peanut butter or it will throw the recipe off.
  • Add peanut butter while cookies are still warm so it melts nicely and sort of absorbs into the cookies a little.
  • Be careful not to over-bake these or the edges will be dry. Plus they’ll continue to cook just a little once removed from the oven from the heat of the baking sheet.

More Peanut Butter Recipes You’ll Love!

 

16 Quick & Easy 30 Minute Recipes! (plus weekly recipe updates)

Peanut Butter Bars
4.50 from 2 votes

Peanut Butter Bars {with Chocolate Frosting}

Peanut Butter Bars are one of the best treats and they're great for parties because they make enough for a crowd! You get a chewy oat cookie base that's loaded with peanut buttery flavor, then it's topped with a layer of peanut butter after baking and finished with a decadent chocolate frosting.
Servings: 30
Prep30 minutes
Cook12 minutes
Ready in: 42 minutes

Ingredients

Frosting

Instructions

  • Preheat oven to 350 degrees. Butter a rimmed 18 by 13-inch cookie sheet.
  •  In a mixing bowl whisk together flour, oats, baking soda and salt. Set aside.
  • In the bowl of an electric stand mixer fitted with the paddle attachment, blend together butter, brown sugar and granulated sugar until creamy. 
  • Mix in eggs one at a time. Blend in 1 cup peanut butter and the vanilla. With mixer set on low speed, slowly add in flour mixture and mix just until combined.
  • Drop cookie dough onto prepared baking sheet. Spray hands with non-stick cooking spray and spread dough into an even layer. 
  • Bake in preheated oven 12 - 15 minutes until golden (see notes).
  • Remove from oven and cool 5 minutes, then dollop remaining 1 cup peanut butter by spoonfuls over top. Let sit 1 minute then spread peanut butter into an even layer to cover top.
  • Melt butter in a medium saucepan. Stir in cocoa, milk and salt and bring mixture just to a boil over medium heat. 
  • Remove from heat and whisk in vanilla, then stir in powdered sugar and mix until well combined (if needed you can add 1 Tbsp hot water to thin). 
  • Immediately pour over bars and spread into an even layer. Allow frosting to set then cut into squares. Store in an airtight container.

Notes

  • Be careful not to over-bake or edges will be dry, don't wait for it to be golden brown. They should be puffed and beginning to set but still soft.
  • Recipe adapted from Taste of Home
Nutrition Facts
Peanut Butter Bars {with Chocolate Frosting}
Amount Per Serving
Calories 339 Calories from Fat 162
% Daily Value*
Fat 18g28%
Saturated Fat 7g44%
Cholesterol 35mg12%
Sodium 190mg8%
Potassium 170mg5%
Carbohydrates 40g13%
Fiber 2g8%
Sugar 26g29%
Protein 6g12%
Vitamin A 300IU6%
Calcium 26mg3%
Iron 1.3mg7%
* Percent Daily Values are based on a 2000 calorie diet.
Nutrition values are estimates only. See full disclaimer here.