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Bake Sale Peanut Butter Oat Bars. Think a doughy, buttery peanut butter cookie base made with old-fashioned oats, baked until just set, then layered with creamy peanut butter. On top, a rich chocolate frosting is poured over the bars to sandwich in all that peanut butter goodness. Once the frosting sets, it creates that old-fashioned crackly icing we all know and love. These bars are chocolatey, peanut buttery, and so delicious!
I’m back today with even more bake sale–inspired treats. I’m honestly not even sure if bake sales are still much of a thing, but I love baking up sweets that are perfect for sharing this time of year.
Bake sale or not, these are the bars to bring for game day, family parties, or dinners with friends. It’s that time of year when everyone’s starting to gather again after a summer of fun and easy nights.
Inspired by the peanut butter oat bars our school lunchroom used to serve, these are guaranteed to be a hit with everyone. And if you do end up baking them for the school bake sale, they’ll definitely be the first treat to disappear.
These are the details
Ingredients
- salted butter
- creamy peanut butter – crunchy will work too!
- brown sugar
- vanilla
- eggs
- vanilla extract
- flour
- old-fashioned oats
- baking soda
For the Icing
- powdered sugar
- cocoa powder
- vanilla
- dark or milk chocolate – I love dark
Special Tools
For these peanut butter bars, you need two mixing bowls and an electric mixer. I love this half sheet pan for baking.
The Steps
Step 1: Make the cookie dough
In a mixing bowl, beat the butter together with the brown sugar, peanut butter, and vanilla. Add the eggs and beat until combined. Mix in the flour, oats, baking soda, and salt.
Mix, mix, mix until you have a soft dough!
Step 2: Bake
Line a 9×13-inch baking dish with parchment paper. Or, if you prefer thinner bars, use a slightly larger half sheet pa, something are a 13×18 inch half sheet pan.
Bake for about 20 minutes (22 minutes if using a sheet pan), until just set.
Step 3: The peanut butter layer
As soon as the bars come out of the oven, spread the remaining peanut butter evenly over the top. The heat from the bars will melt the peanut butter, making it easy to spread into a smooth layer.
Let the peanut butter stiffen and set. To speed things up, pop the pan in the fridge or freezer until firm.
Step 4: The chocolate icing
Whisk together the powdered sugar, cocoa powder, vanilla, and melted milk chocolate until smooth and fudgy. Pour the icing over the bars and spread evenly.
Let the icing set and harden, or dig in right away while it’s still gooey—so delish!
Tip
If you’d like a shiny, glossy finish to your icing, whisk in a couple teaspoons of meringue powder. It helps the frosting set without smudging. Totally optional, but a fun extra!
Whether it’s back-to-school, game day, or just a family night in, these bars are the perfect dessert to bake, share, and enjoy. And if you’ve got kids around, this is an easy recipe they can help with too!
Looking for easy “lunchroom” style back-to-school desserts? Here are a few ideas:
Chocolate Peanut Butter Pretzel Blondies
Giant Salted Espresso Hot Fudge Cookies
Lastly, if you make these Bake Sale Peanut Butter Oat Bars, be sure to leave a comment and/or give this recipe a rating! Above all, I love to hear from you guys and always do my best to respond to each and every comment. And of course, if you do make this recipe, don’t forget to tag me on Instagram! Looking through the photos of recipes you all have made is my favorite!
Bake Sale Peanut Butter Oat Bars
Servings: 24 bars
Calories Per Serving: 322 kcal
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
Ingredients
- 2 sticks (1 cup) salted butter, at room temperature
- 1 cup creamy peanut butter
- 1 cup brown sugar
- 2 large eggs, at room temperature
- 1 tablespoon vanilla extract
- 2 cups all-purpose flour
- 2 cups old fashioned oats
- 1 teaspoon baking soda
- 1 teaspoon salt
Icing
- 1 1/2 cups creamy peanut butter
- 2 cups powdered sugar
- 2 tablespoons unsweetened cocoa powder
- 1 tablespoon vanilla extract
- 2 ounces dark or milk chocolate melted
Instructions
- 1. Preheat the oven to 350° F. Line a 9×13 inch baking dish or 13x18 inch half sheet pan, with parchment paper.2. In a large mixing bowl, beat together the butter, brown sugar, 1 cup of peanut butter, and vanilla until combined. Beat in the eggs. Add the flour, oats, baking soda, and salt. 3. Press/spread the dough out into the prepared dish. Bake for 18-22 minutes, until just set in the center. Remove from the oven and dollop 1 1/2 cups of peanut butter over the bars, lightly spreading the peanut butter in an even layer. Let cool completely, you can chill in the fridge to speed this up.4. Meanwhile, make the icing. In a bowl, whisk together the powdered sugar, cocoa powder, vanilla, and 3 tablespoons of water until smooth. Stir in the melted chocolate. If your icing is too thick, thin with 1-2 tablespoons additional water. Spread the icing over the bars. Let set for 1-ish hour…or slice, snack, and enjoy!
This post was originally published on August 22, 2025
These turned out great and super delicious!
Hey Marie! Thank you so much for trying out the recipe! So happy to hear you loved these PB bars! 🙂 xT
The texture was soooo bad.
Hey Sharon! Oh no! So sorry to hear that! Is there anything I can do to help? Let me know! 🙂 xT
These were really easy to make and they tasted so good. The only this I didn’t love was the texture so what I would change is to add less oats or to make them without oats. The oats are a little crunchy/hard. The bars are better the next day because the oats get a little bit softer I think. But then I found there’s another peanut butter bar recipe you have without oats so I’ll probably try that next time
Hey Anne! So happy to hear you loved these peanut butter bars! Thank you for the feedback, I appreciate it! 🙂 xT
I’m having a hard time figuring out which of your chocolate/peanut butter bars to make. Why do you have so many? Which is the one that comes out the best?
Hey Wendy! It just depends on what type of bar you’re looking for! Let me know if I can help! 🙂 xT
Tieghan, I mean this kindly, no one is able to sit on your website and have a multi-message conversation with you when you take so long to reply, there is no indication you’ve replied, and the message will have to go through both a manual and automatic filter. I see you often not answering people’s questions and instead asking them a question, which is so frustrating. Wendy’s question was clear. You have a million different bars with chocolate and peanut butter layers. You can assume she is fine with oats, shortbread or cereal as the base given she didn’t specify. If you can’t sift through your own recipes, how do you expect us to? I just wish you’d try to answer questions without just responding with a platitude and asking them to again jump through hoops to send another message.
Please please try to avoid doing this all the time.
Hi Wendy, thank you for taking the time to share your thoughts so openly. I really do appreciate your feedback and I hear your frustration. I try my best to answer questions as clearly as possible, but I know sometimes my replies can feel indirect or delayed. I’ll definitely keep your note in mind and work on being more straightforward in my responses so you’re not left waiting or having to re-ask. I truly value the time you spend here and your patience means a lot! Thank you again, and have a lovely day! xT
This is the second bar dessert recipe that I’ve tried from this website where the base layer crumbled so badly that it’s difficult to enjoy.
Hey there! I am so sorry you didn’t enjoy these peanut butter bars! Thank you for letting me know! xT
These turned out so dry & overall just disgusting.
Hey Quinn! I am really sorry you didn’t enjoy these, please let me know if there’s anything I can do to help! xT
These look so yummy! My kid’s school does a bake sale at Christmas time every year! It’s different than in the old days….they set up a day and everyone who participates has to bake and package their baked goods in the school’s kitchen and it does have to be tree nut free. I would love some good tree nut free bake sale ideas this year! Cookies, candies and breads are popular. Would love some ideas of things you can make a lot of fairly quickly, and with affordable ingredients would be awesome!
Hi Kelsie! That sounds so fun! Let me share some ideas below! 🙂
https://fett-weg.today/brown-butter-rice-krispie-treats/%3C/a%3E%3C/p%3E
https://fett-weg.today/magic-chocolate-chip-cookies/%3C/a%3E%3C/p%3E
https://fett-weg.today/christmas-lights-cookies/%3C/a%3E%3C/p%3E
Hope this helps! Have a great week! xT
Good flavor, too dry and crumbly for my taste.
Hey Mary! I’m really sorry you didn’t enjoy this recipe! Thank you for this input! xT
These were such a fail.
Hey Sally! I am really sorry you didn’t enjoy this recipe, thank you for letting me know! xT
These are just not worth the effort. They taste ok, but not enough chocolate and it is weird that the peanut butter layer is straight PB- no powdered sugar vanilla etc. The cake part is texturally boring. It just crumbles apart and overall has an undesirable lack of structure.
Hey Isaac! I am so sorry these didn’t turn out for you! Thank you for letting me know, I appreciate this input! xT
The favor on these bars was so yummy but mine felt a little dry. Not sure what I did. But we still ate them lol
Hey Ginger! Thank you for the input! I really appreciate you trying out the recipe! Have a great Monday! xT
These were so dry & the icing was lackluster.
Hey Rita! I’m really sorry you didn’t enjoy this recipe, thank you for the feedback! Always appreciate it! xT
I feel like these comments are a little silly. While some children do have not allergies most do not and I wouldn’t exactly say it’s out of touch for her seeing if she doesn’t have children. The peanut butter and chocolate combo is loved by many that being said, these were OK. The crust was good but a little dry the peanut butter layer was definitely necessary for more of that flavor and the topping could’ve been more fudgey. It felt a little too thin and not chocolatey enough, but like someone else commented she has many other chocolate peanut butter recipes to try. I liked that these were easy and made a large batch. My kids loved them.
Hi Chloe! Thanks for trying the recipe and sharing your thoughts! I’m glad your kids loved them. Great feedback on the peanut butter layer and topping, it’s helpful to know what worked and what could be a bit more chocolatey. Appreciate you taking the time to share! xT
Just made it and it turned out great! Not too sweet at all. Do you normally store it in frig after?
Hi Shauna! Thank you so much! You can either store these in the fridge or counter in an air tight container! 🙂 xT
These are so good. The cookie layer is soft and chewy and the chocolate is sweet and goes nicely with the peanut butter. I didn’t like the texture of the icing. It needed fat, so I added a couple of teaspoons of peanut butter and it blended nicely. Yum!
Hi Karen! Wow thank you so much! So happy to hear you’re loving the peanut butter bars! 🙂 xT