Vintage peanut butter bar recipe! These baked chocolate peanut butter bars are made with oatmeal and are the original, old-fashioned lunch lady peanut butter bars.
There are some foods that are love-at-first bite. For me, that was the case with these peanut butter bars. I first had these bars in my college cafeteria, and I was hooked!
These chocolate peanut butter bars have a layer of peanut butter oatmeal cookie topped with a layer of peanut butter and then covered with a layer of rich chocolate frosting. So, there’re a pretty perfect dessert for people who love peanut butter and chocolate.
How To Make Peanut Butter Bars
Beat the butter and sugars together until well-combined. Add the eggs and vanilla.
Mix in part of the peanut butter. Stir in the flour, baking soda, and salt just until incorporated and then stir in the oats.
Spread into pan and bake until golden brown. Beat the remaining peanut butter until fluffy.
This will help it spread better over the warm bars. Drop spoonfuls of peanut butter over the warm bars and spread in one direction.
To make the frosting, add the butter, milk, and cocoa powder to a saucepan. Bring to a boil.
Remove from heat and stir in vanilla and powdered sugar. Pour over bars and let cool before cutting and serving.
- Peanut Butter: Use regular peanut butter (Skippy, Jif, etc.) in this recipe. The natural peanut butters without oil and sugar don’t work well in this recipe.
- The bars are rich! The servings are fairly generous since the bars are so rich, so feel free to cut the bars into smaller servings.
- In order to keep the peanut butter from pulling up the bars, the peanut butter is whipped until light and easily spreadable. Then, the peanut butter is dropped by spoonfuls and spread to cover the bars.
- When spreading the peanut butter, going in one direction will help to keep the bars from coming up.
- Powdered Sugar: If your powdered sugar is lumpy, sift it before adding it to the frosting. This will help it mix in easily.
- Frosting: The cooked chocolate frosting takes a little longer to make than a chocolate buttercream, but it’s more true to the original bars. If you prefer buttercream, this chocolate buttercream frosting is my favorites.
I prefer to chill the bars prior to serving, but they can be served cold or at room temperature. I also store them, covered, in the fridge.
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Peanut Butter Bars
Peanut Butter Bars
- 1/2 cup butter softened
- 3/4 cup brown sugar
- 1/2 cup granulated sugar
- 2 large eggs
- 1 teaspoon vanilla
- 1 ½ cups peanut butter1 divided
- 1 ½ cups all-purpose flour
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 1 ½ cups rolled oats
- 1/2 cup butter
- 1/4 cup milk
- 1/4 cup unsweetened cocoa powder
- 1 teaspoon vanilla
- 3 cups powdered sugar
- Preheat oven to 350 F. Grease a jelly roll (10x15-inch) baking pan. Set aside.
- In a large bowl, beat butter and sugars together until well-combined, about 2-3 minutes.
- Add eggs and vanilla, and mix until combined, scraping down the bowl as needed.
- Mix in 3/4 cup peanut butter until well-combined, about 1-2 minutes.
- Stir in flour, baking soda, and salt until almost incorporated.
- Stir in oats until just incorporated.
- Spread batter into prepared pan.
- Bake 12-15 minutes, or until golden brown.
- Let bars cool in pan for 10 minutes.
- Beat remaining 3/4 cup peanut butter until whipped and fluffy.
- Drop spoonfuls, and gently spread to cover bars.2 Set aside.
- In a medium saucepan, add butter, milk, and cocoa powder.
- Bring just to a boil over medium heat.
- Remove from heat, and stir in vanilla and powdered sugar3 until combined.
- Pour over bars.
- Let cool in the pan completely before cutting and serving.
- For this recipe, you'll want to use regular peanut butter with sugar. Natural peanut butter (just peanuts and salt) won't work well in these bars.
- Spreading the peanut butter in one direction helps to keep the peanut butter from pulling up the bars.
- If your powdered sugar is lumpy, sifting it before adding it to the icing will help it to stir in easily and will help keep the frosting from having lumps.
- I prefer to chill the bars prior to serving, but they can be served cold or at room temperature. I also store them, covered, in the fridge.
- Nutrition values are estimates.
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Originally published 4/3/18. Updated with new photos and tips 2/17/20.
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Comments & Reviews
Quick question please… (made these tonight.) Everything went great great! Easy/ instructions are perfect… my question : minor: my frosting did not appear quite as thick as yours shows in your picture. Although I will say it tasted great! They’re chilling in the fridge currently. Can’t wait to try them. Just wasn’t sure if I did something wrong re: frosting. Many thanks! Happy 4th to you and yours!
Thank you! You too! Did chilling help the frosting to set up? If not, I’m happy to help you troubleshoot.
These were so good! Loved lots of peanut butter flavor.
These were absolutely divine. I was looking for oatmeal recipes for my sister who is breastfeeding and she wolfed them down ! Will definitely be making more. Thanks for the great recipe!
Yum!! Thanks for the great recipe! Made these for my family, and everyone ate them all. Everyone was fighting over the last piece. Guess I need to make them again soon! LOL
Thank you! Glad your family liked it! Thanks for taking the time to come back and comment!