Vintage peanut butter bars are a tasty treat! 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. That was the case for me 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.
“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” – Sarah
Ingredient notes and substitutions
- Butter: I use salted butter in this recipe.
- Brown sugar: Light brown sugar or dark brown sugar will work in this recipe.
- 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.
- Milk: Any milk, from skim milk to whole milk, will work in this recipe. Nondairy milk, like almond milk, will also work.
- Powdered sugar: If your powdered sugar is lumpy, sift it before adding it to the frosting. This will help it mix in easily.
How to make peanut butter bars
Here you’ll find step-by-step photos showing how to make this recipe. The full recipe, including ingredients, is given below.
Step 1: Mix in part of the peanut butter.
Step 2: Beat the butter and sugars together until well-combined.
Step 3: Add the eggs and vanilla.
Step 4: Stir in the flour, baking soda, and salt just until incorporated and then stir in the oats.
Step 5: Spread into pan.
Step 6: Bake until golden brown.
Step 7: Beat the remaining peanut butter until fluffy. This will help it spread better over the warm bars.
Step 8: Drop spoonfuls of peanut butter over the warm bars and spread in one direction.
Step 9: To make the frosting, add the butter, milk, and cocoa powder to a saucepan. Bring to a boil.
Step 10: Remove from heat and stir in vanilla and powdered sugar.
Step 11: Pour over bars and let cool before cutting and serving.
Recipe Tips!
- Spreading the peanut butter: 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. Spreading the peanut butter in one direction helps to keep the peanut butter from pulling up the bars.
- Powdered sugar: 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.
- 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.
- Chilling: 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.
- Servings: 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.
Storage
I prefer to chill the bars prior to serving, but they can be served cold or at room temperature. I store them in an airtight container in the refrigerator. The bars will keep for up to 5 days when properly stored in the fridge.
More peanut butter recipes!
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Peanut Butter Bars
Ingredients
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 butter divided
- 1 ½ cups all-purpose flour
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 1 ½ cups rolled oats
Chocolate Icing
- 1/2 cup butter
- 1/4 cup milk
- 1/4 cup unsweetened cocoa powder
- 1 teaspoon vanilla
- 3 cups powdered sugar
Instructions
- Preheat oven to 350 F. Grease a jelly roll (10×15-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. Please see the notes above the recipe for tips on spreading the peanut butter. 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.
Notes
- Butter: I use salted butter in this recipe.
- Brown sugar: Light brown sugar or dark brown sugar will work in this recipe.
- 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.
- Milk: Any milk, from skim milk to whole milk, will work in this recipe. Nondairy milk, like almond milk, will also work.
- Powdered sugar: If your powdered sugar is lumpy, sift it before adding it to the frosting. This will help it mix in easily.
- Nutritional values are estimates.
Nutrition
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Originally published 4/3/18. This recipe is regularly updated.
Reader Interactions
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Comments & Reviews
rose33 says
Don’t have a jelly roll pan. Any other pan suggestions? 13×9?
Kate says
Hi! Unfortunately, there isn’t a perfect substitute for a jelly roll pan, and I’ve only made this recipe in a jelly roll pan. The two closest pan sizes are going to be either a 9×13 or a half sheet pan. A 9×13 has a lower volume, so the bars will be thicker and take longer baking. A half sheet pan has a bigger volume, so the bars would be thinner and take less time.
Donna says
can you use store purchased chocolate icing and doctor it up?
Kate says
I haven’t tried that with this recipe, but I would guess that you could do that. The only thing I’m not sure about would be how the frosting would set back up after it is spread on the warm bars.
rose333 says
I don’t have a jelly roll pan. What other pan can I use?
Marie says
Haven’t made it yet. I don’t have a Jelly Roll pan, what other kind of pan can I use?
Will put another comment once made.
Sheila says
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!
Kate says
Thank you! You too! Did chilling help the frosting to set up? If not, I’m happy to help you troubleshoot.
Deb says
These were so good! Loved lots of peanut butter flavor.
Linda says
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!
Sarah says
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
Kate says
Thank you! Glad your family liked it! Thanks for taking the time to come back and comment!