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Peanut Butter Bars better than the Lunch Lady’s! Full of peanut butter, oats and the most amazing chocolate frosting. You’ll never need another peanut butter bar recipe again!

peanut butter bar recipe

Peanut Butter Oatmeal Bars

Peanut butter bars are a delicious dessert bar that brings you the wonderful combination of chocolate and peanut butter in a cookie bar style. Honestly, they remind me of elementary school when I could pay .50 cents for a peanut butter bar at lunch time! (Back when peanuts were aloud in schools.. 😉 )

While this peanut butter bar recipe is one of the baked variety, it is worth every single second of waiting. I promise with everything that my heart possesses. These are 100% the best peanut butter bar recipe I’ve ever made. I have tested this recipe for nearly a year now, I am so excited to say that it is perfected. And that you should try it.

peanut butter bars with chocolate icing

What’s In Peanut Butter Bars Recipe?

To make your peanut butter bars you will need a few basic ingredients that you most likely already have in your pantry! (Best kind of recipe, right?) I’ll go through all of the details below along with any possible substitution suggestion.

  • Salted Butter: We will want the butter either softened or room temperature. If you don’ have salted butter and only have unsalted on hand, that is fine! Just add an extra pinch of salt to the recipe to make up for it.
  • Peanut Butter: I use creamy peanut butter but crunchy would definitely work well if that is what you have on hand. I generally use the store brand peanut butter, the cheap stuff. 😉 I have not tested this recipe with natural peanut butters so I am unsure of how that could change the outcome of the recipe.
  • Granulated Sugar
  • Brown Sugar
  • Eggs
  • Vanilla Extract
  • All Purpose Flour
  • Old Fashioned Oats: I haven’t tested this recipe using quick oats so I would strongly suggest using old fashioned oats for this recipe.
  • Salt
  • Baking Soda

For the chocolate icing you will need:

  • Salted Butter
  • Cocoa Powder: We are looking for unsweetened cocoa powder here. Not hot cocoa powder. 😉 Again, I usually use the generic brand.
  • Milk: I just use what I have on hand, sometimes that is skim milk and sometimes it is whole milk! It all will be sufficient for this recipe.
  • Powdered Sugar
  • Vanilla

peanut butter chocolate bars, cut and served

How to Make Peanut Butter Bars

Making peanut butter bars is very similar to making cookies, only you don’t scoop and roll the dough. You’ll press it into a 9×13 pan! Easy peasy, lemon squeezy.

To make the chocolate frosting, we will actually make this on the stovetop. This is not the usual way of making a chocolate frosting, I know, but trust me on this. Melting all of the ingredients together on the stove top and then pouring the frosting onto the warm peanut butter bars will create a thick, dense layer of fudgy chocolate that is to die for! You can find specifics in the printable recipe card below.

peanut butter bars recipe card

How to store Peanut butter bars?

Keep your peanut butter bars inside of an airtight container at room temperature for up to a few days. For longer storage, you can keep them in the freezer, but make sure to let them come to room temperature before eating so that you don’t hurt your teeth. They can be quite hard when frozen!

Can I make peanut butter bars dairy free?

Absolutely! With dairy free chocolate chips, vegan butter and a dairy free milk you can easily make this recipe dairy free and still have it turn out delicious!

pin image for peanut butter bar recipe

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5 from 10 votes

Peanut Butter Chocolate Bars

Peanut Butter Bars better than the Lunch Lady's! Full of peanut butter, oats and the most amazing chocolate frosting. You'll never need another peanut butter bar recipe again!
Prep Time: 20 minutes
Cook Time: 20 minutes
Cooling Time: 45 minutes
Servings: 24 squares


Peanut Butter cookie Layer

  • 1/2 cup (111g) salted butter
  • 1 cup (246g) peanut butter
  • 1/2 cup (115g) granulated sugar
  • 1/2 cup (123g) brown sugar
  • 2 eggs
  • 2 tsp vanilla
  • 1 1/2 cups (228g) all-purpose flour
  • 1 cup (100g) old fashioned oats
  • 1/2 tsp salt
  • 1 tsp baking soda

Chocolate Icing

  • 1/2 cup (111g) salted butter
  • 4 tbsp cocoa powder
  • 6 tbsp milk
  • 1 lb powdered sugar
  • 1 tsp vanilla


  • Preheat oven to 350°.
  • Cream together peanut butter, butter and sugars until light and fluffy with either a stand mixer or electric hand mixer.
  • Add in the eggs and vanilla, mix until just combined.
  • Add in the flour, old fashioned oats, salt and baking soda.
  • Mix until the dough forms. Dough will be slightly sticky.
  • Spread and press the dough into the bottom of a greased 9x13 pan.
  • Bake at 350° for 18-20 minutes.
  • Once the peanut butter bars come out of the oven, make the frosting.
  • To make the frosting, melt the butter, cocoa powder and milk in a medium saucepan pan over medium heat. Bring to a soft boil.
  • Once boiling, remove from heat and whisk in the powdered sugar and vanilla.
  • Let the icing cool for 10 minutes. Stir the icing to break up the crusting on top and then pour over the peanut butter bars.
  • Allow to cool completely before cutting. (You can put it in fridge to speed up the process, if desired.)


Calories: 290kcal | Carbohydrates: 39g | Protein: 5g | Fat: 14g | Saturated Fat: 6g | Cholesterol: 34mg | Sodium: 227mg | Potassium: 120mg | Fiber: 1g | Sugar: 28g | Vitamin A: 262IU | Calcium: 21mg | Iron: 1mg
Like this recipe? Rate and comment below!

About Karli Bitner

This blog is a little glimpse into my kitchen, family & life. I hope you’ll giggle the days away with me and enjoy the craziness that goes on at my house. If you are Cookie obsessed like I am, check out my Sister Site, Cookies for Days.

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Recipe Rating


  1. 5 stars
    I was very intrigued when I saw this recipe. Most peanut butter bars use Graham cracker crumbs which I hate so I was happy when I saw this recipe did not. These were beyond good. So full of flavour. The only thing I might do is process the oatmeal so it is just a bit finer in the batter. No matter what I will definitely make them again. So happy I found Karli.

  2. 5 stars
    OMG I’m such a sucker for any dessert with PB and chocolate but I’m not usually blown away. These bars are PERFECT. I did a full recipe in a 9×9 pan so they were so thick and the frosting was about as thick as the bars. I literally cleared them out so fast with my husband. The frosting is addicting. Seriously, so freaking good. Thanks for the recipe Karli! I will definitely be making these again soon. Also – I’ve never written a recipie review, it was just that good.