These Peanut Butter Cookie bars are reminiscent of a retro dessert that used to be served at many cafeterias across the US! They’re incredibly soft, rich in peanut butter flavor, with bite from some added oats, and covered in a smooth and rich chocolate icing. My favorite thing about this recipe (besides how good they are) is how many they make. They bake up in a sheet pan, and because they’re rich, you can cut them fairly small, so it’s the perfect dessert to feed a crowd. I often take them to parties and potlucks because of this (as long as I’m sure it’s a function that’s safe for peanut recipes!)
Ingredients and Equipment List
- Peanut Butter – you can use creamy or chunky peanut butter. I’ve never tried this recipe with a natural peanut butter (if you do, let me know!) But standard brands like Skippy and Jiff work great.
- Butter – unless you have an allergy or food intolerance, I recommend real butter (salted).
- Sugars – you’ll use a combination of granulated white sugar and light brown sugar.
- Oats – quick oats give these bars extra chew. If you don’t have quick oats, I like to pulse my old fashioned oats in the blender a few times to break them up just a bit.
- Cocoa Powder – cocoa powder is used in the icing, and you’ll want to used unsweetened.
Instructions
These cookies are incredibly quick and easy to whip up. It’s simply a basic cookie dough, frosted with the icing while it’s still warm.
- Make Dough: This is standard cookie making procedure here. You’ll cream together butter and sugar, then add peanut butter, eggs, and vanilla.
- Whisk together your dry ingredients and add those until combined.
- Stir in the oats.
- Press into a parchment-lined baking sheet and bake.
- Now, right here there’s an optional step: If you want to go full send, you can also drizzle on some melted peanut butter on top of the warm bars so there’s a layer of peanut butter underneath the chocolate icing. I used to always make them that way, and it’s deliciously indulgent, but I think they’re equally fantastic (and a little less rich) with out the PB layer so I usually skip that step these days.
- Mix up your frosting and spread on top of warm bars.
- Wait until they’re cool to slice!
Frequently Asked Questions
- Can these be made ahead of time? YES! They are are actually extra great made ahead of time (dare I say better on day 2?) Since they’re super soft they just seem to get better. You can cover the cooled pan in foil or plastic wrap and cut on day 2, or keep the sliced bars in an airtight container. I would also imagine they freeze well, though I haven’t tried that.
Chocolate-Frosted Peanut Butter Cookie Bars {Aka: School Lunch Peanut Butter Fingers}
Unbelievably soft and chewy peanut butter cookies in bar form, topped with a rich chocolate glaze. Made in a sheet pan for high yield!
Ingredients
- Cookie Base1 cup real butter 2 sticks at room temperature1 cup granulated sugar2 cups brown sugar1 1/2 cups peanut butter, chunky or smooth 3 eggs2 teaspoons vanilla1 1/2 teaspoons baking soda1/2 teaspoons table salt3 cups all purpose flour3 cups quick oatsoptional: an extra 3/4-1 cup peanut butter, see notes in recipe below
- Fudge Frosting4 cups powdered sugar1/2 cup cocoa powder1/4 teaspoon table salt1/3 cup butter softened1/3 cup boiling water1 teaspoon vanilla extract
Instructions
- Preheat oven to 350 degrees. Spray a rimmed cookie sheet (standard half-sheet pan) lightly with non-stick spray, or line with parchment paper, and set aside.
- Cream butter and sugars for 3-4 minutes, until creamy and slightly fluffy. Add peanut butter and vanilla and beat until combined. Add eggs, one at a time and beat between each addition. Combine flour, baking soda, and salt and add mixture to dough. Beat to combine. Add oats and mix until incorporated.
- Press dough into prepared pan into a flat layer. Bake for about 20-30 minutes, until puffed and set, but not browned on the edges. The center should be puffed and set, but still soft. The edges of the cookie bars should be puffed and kind of cracked like a baked cookie looks.
- Optional Step: Some people like to drizzle on a layer of melted peanut butter onto the warm bars so there's a layer of pb under the icing. If you'd like to do that step, I just microwave 3/4-1 cup of pb until it's melted and smooth and can easily be drizzled over the top of the warm bars. You'll want to spread it gently so you don't tear your cookie layer. It's deliciously indulgent with or without this extra pb layer!
- When cookies are just about done, prepare frosting. Whisk together powdered sugar, cocoa powder and salt. Add butter (make sure it’s really soft, you can microwave it if you need to- even melted is ok!), boiling water, and vanilla. Beat until smooth and glossy.
- When cookie crust is done baking, pour warm frosting over the top and spread into an even layer. Let bars cool before cutting in.
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Questions & Reviews
My mom *was* a school lunch lady and has always made incredible cookies (she is 94 now, I visited her last week, we made cookies!). BUT we never made these! My daughter is a pb addict so I can’t wait to make these!
This is a great recipe and I have made it many times. After a few issues, there are a couple of things I do for success. I line the pan with foil, it makes it easier to remove the bars. I bake it until it has a moist crumbs attached when testing with a toothpick, as it finishes baking outside of the oven. I also allow the cookie layer to cool completely, as a too warm cookie, topped with hot peanut butter, can cause the cookie to sink in spots. After I top it with the melted peanut butter, I put the pan in the fridge for a few minutes to firm it up, before topping with the frosting, which helps these layers stay separate. I have to add additional hot water to make the frosting spread nicely, as 1/3 cup just makes a lump, no matter the humidity level. To make the presentation beautiful, I remove the bars using the foil as a sling, and cut off the high edges, then cut these into skinny bars, as they are super rich. Thanks Sara for the great blast from the past!
Would these turn out ok with natural peanut butter? Do any adjustments need to be made to the recipe?
I never use natural PB in recipes so I’m not sure; you’d have to experiment. Let me now what you find out!
Turned out fabulous! I put the extra peanut butter in the frosting, yummy! Thanks for the great recipe.
I made these today for a playdate and gave half the pan to my neighbor…I was just noticing the picture with the oats…yeah, totally didn’t add those, and they’re still fantastic. The other mom walked in and said, ‘those look just like something they served at my cafeteria!’ seriously, I missed the good lunch boat I think!
Big fan! I have your cookbook! So my husband said for Father’s Day he wanted these, so I was happy to see that you had the recipe on you site. But what I really want to talk about is how AMAZING the chocolate frosting is! Omg! I have never made fchocolate frosting from scratch before! I have been missing out. My life is complete now. It took all the will power I had not to eat it out of the bowl while the bars were baking!
Yay! I have been looking for this recipe for years!!! These are exactly like they served us at Hamden High School in Connecticut! Best Part of School! THANK YOU!!!
Just made these. If people weren’t watching, the pan would be gone, and I would be lying in a heap on the floor so full I couldn’t move.
I just saw a similar recipe on another site, so I checked out yours to see if you have one posted, and great, you do! But, I am hoping to make these today, and now I am a little worried. The other recipe called for half the flour, oats, and almost everything, but it was still in the same size pan. They didn’t look overly thin, so how thick are yours? My pan is a jelly roll pan, so I think it is 12 x 16 instead. Thanks!
Mine fit perfectly in a standard jelly roll pan. That’s all I can tell ya!
The BEST dessert that I’ve had a potluck in YEARS! I couldn’t stop eating them and took some to go too! It was so hard to not eat the entire pan. I am going to make this for my office and I know that they will love it. I wasn’t sure when I saw it in the pan, it just looked like any other bar. Wait until you sink your teeth into them…… SO DELICIOUS!!