Old Fashioned Peanut Butter Bars


Old fashioned peanut butter bars are yummy, easy to make and keep well. The recipe comes from my mum’s baking box and has been used by the family for years.  Peanut butter is one of the most delicious and versatile products in existence. Some of my favorite desserts include peanut butter, chocolate and Reese’s pieces. And when I found this recipe that takes an old fashioned tin full of peanut butter cups, it was love at first bite. I bet they’ll be your new favorite too.

The BEST Lunch Lady Peanut Butter Bars Recipe

These Lunch Lady Peanut Butter Bars are the EXACT recipe they once served in schools! These peanut butter bars have a soft, chewy peanut butter cookie base, creamy peanut butter center and chocolate buttercream on top. These are the best peanut butter bars of all time!





Peanut Butter Bars

  • 1 cup butter softened
  • 1 cup sugar
  • 1 cup brown sugar firmly packed
  • 1 teaspoon vanilla extract
  • 2 large eggs
  • 2½ cups peanut butter divided
  • 2 cups old fashioned oats
  • 2 cups flour
  • 1 teaspoon baking soda
  • 1 teaspoon salt


  • ½ cup butter softened
  • ¼ cup milk
  • 2 teaspoons vanilla
  • 4 Tablespoons cocoa powder
  • 3 cups powdered sugar


  • Preheat oven to 350 degrees F.
  • In a large bowl, cream together butter, sugar and brown sugar together.
  • Add vanilla, eggs, and 1 cup of the peanut butter; stir to combine.
  • Add oats, flour, baking soda and salt and mix until well combined.
  • Spray a baking sheet (half sheet jelly roll pan that is approximately 17.8 x 12.8 x 1 inch) with nonstick cooking spray and spread out dough in an even layer.
  • Bake for 15 minutes and remove from oven.
  • Drop remaining peanut butter (about 1 1/2 cups) by very small spoonfuls (we use a baby spoon) all over on top of warm bars. Let set for about 5-6 minutes and gently spread when peanut butter has begun to melt. It will spread easily when the peanut butter has softened on the warm bars. Don’t try to spread it while still thick.
  • Then let the bars cool until peanut butter has set up.
  • While cooling, mix together frosting ingredients with a hand mixer until smooth and spread on top of bars.
  • Cut into bars and serve.


  • These bars are made in a half sheet pan and you can cut them into as many bars as you need.
  • We like a bigger bar, so we typically cut a pan of these cookie bars into 24 squares, but you could easily cut them into 48 for a smaller serving.


Calories: 459 kcal · Carbohydrates: 51 g · Protein: 10 g · Fat: 26 g · Saturated Fat: 10 g · Trans Fat: 1 g · Cholesterol: 44 mg · Sodium: 377 mg · Potassium: 248 mg · Fiber: 3 g · Sugar: 35 g · Vitamin A: 378 IU · Calcium: 34 mg · Iron: 2 mg

F.A.Q.S for Classic Peanut Butter Bars

Do you use instant oats or old-fashioned oats?

I almost ALWAYS use old-fashioned oats. I think instant oats dry out any type of cookie dough. Plus, old-fashioned oats give it a great texture.

I need to serve these quickly, how can I speed up the process.

You definitely don’t want to spread that frosting on while the bars are still warm. If you’re in a rush, I would suggest putting the entire pan in the freezer for 10-15 minutes to help it cool faster.

Is there a brand of peanut butter you would recommend?

I will always suggest using Jif brand peanut butter because I find it the best. I find Skippy to be too sweet, but to each their own. Any brand will work here. However, I would not use an all-natural brand because that will be too runny for this recipe.

Classic Peanut Butter Bars

These classic peanut butter bars will transport you right back to your childhood. Not only are they fast to make, but will disappear quickly.



For the Cookie Dough

  • ½ cup butter, softened
  • ½ cup brown sugar
  • ½ cup white granulated sugar
  • 1 egg
  • ½ tsp vanilla
  • ½ tsp baking soda
  • ¼ tsp salt
  • 1 cup all-purpose flour
  • 1 cup old-fashioned oats
  • ½ cup creamy peanut butter, plus more for spreading on top

For the Frosting

  • 3 tbs cocoa powder
  • 3 cups powdered sugar
  • 4 tbsp melted butter
  • 2-3 tbsp milk
  • 1 tsp vanilla


  • Preheat the oven to 350° and grease a 9×13 pan and set aside.
  • In the bowl of an electric mixer, cream together the butter and sugars until light and fluffy. This should take about 1-2 minutes.
  • Add in the egg and vanilla. Mix well. Scrape down the sides of the bowl.
  • Add in the baking soda, salt, flour, and oats. MIx until incorporated.
  • Finally add in the peanut butter and mix.
  • Press the dough in the the bottom of the pan.
  • Bake for 20-25 minutes or until light and golden around the edges.
  • Let it cool for 5 minutes before spreading a thin layer of peanut butter on top. I used about ¼-⅓ extra peanut butter on top.
  • Make the frosting by mixing together all of the ingredients. Add more milk if needed to make the frosting spreadable. Spread on top of completely cooled bars. Serve and enjoy!


Featuring a peanut butter fudge center and a generous amount of homemade chocolate fudge frosting, lunch lady peanut butter bars are a classic childhood favorite! You’re going to love them!

Featuring a peanut butter fudge center and a generous amount of homemade chocolate fudge frosting, lunch lady peanut butter bars are a classic childhood favorite! You’re going to love them!

Close up view of peanut butter bars.

While most kids looked forward to recess, we preferred lunchtime! Once a week, our beloved lunch ladies would whip up these delicious old fashioned peanut butter bars, and we just couldn’t ever get enough of them! We have such fond memories of those days (and those ladies!) that we knew we had to share their recipe with the world. Whip these up to have on hand for snack time, or wow your guests and bring them to your next potluck. No matter when you serve them, we guarantee that the peanut butter lovers in your life will swoon!


Peanut butter is everywhere in lunch lady peanut butter bars! It truly is the star of the show. That said, if you have an allergy or simply don’t like the taste of it, you can replace it with your favorite nut butter. Here are some yummy ideas:

  • Sun butter
  • Cookie butter
  • Almond
  • Cashew
  • Hazelnut
  • Walnut

No matter what kind of nut butter you decide to use, it’s important that you go for one without any added sugar. For all-natural versions, make sure to give it a good stir so that the oils mix together well. No one wants runny peanut butter bars!


Our lunch lady peanut butter bars can easily be made gluten-free if needed! Simply replace the all-purpose flour with your favorite GF version, and make sure to go with GF oats. 


You can use an 18×13 baking tray (as we have), or you can use a 9×13 baking dish instead. Just be aware that if you use a smaller pan, you’ll likely have leftover crust, filling, and frosting.


While lunch lady peanut butter bars aren’t typically served with a topping, we love the idea of adding some fun extras to the homemade fudge frosting. Here are some suggestions to get you inspired:

  • Reese’s Pieces candy
  • Crumbled Reese’s Peanut Butter Cups
  • Peanuts
  • Any other type of nut
  • Chocolate chips
  • Flaky sea salt
  • Chopped pretzels


Our lunch lady peanut butter bars recipe calls for old fashioned rolled oats as they are known for holding their texture even when baked. You can use instant or quick oats in a pinch — they may affect the texture, but it won’t make a difference as far as taste goes!


The classic version of this beloved dessert is made with an oat-filled crust. We love the old fashioned peanut butter bars recipe, but you can also get creative with the crust. Try replacing it with a:

  • Graham cracker crust
  • Oreo crust
  • Saltine crust 
  • Sugar cookie crust
  • Brownie crust
Overhead view of a baking sheet of peanut butter bars.


These old fashioned peanut butter bars freeze up wonderfully! You can feel free to make them in advance, then store them in the freezer for a later date. Simply follow the recipe instructions and let the dish cool completely. We recommend that you cut the bars and wrap them individually in plastic wrap. Place the bars in a freezer-safe bag, and they will keep for up to 2-3 months! When you’re ready to eat them, make sure to let them thaw in the fridge overnight. 


You can store any leftovers in an airtight container in the fridge or on the countertop, depending on whether you like your lunch lady peanut butter bars chilled or at room temperature. Simply wrap them tightly in plastic wrap and they will keep for 5-7 days.

Lunch Lady Peanut Butter Bars

Featuring a peanut butter fudge center and a generous amount of homemade chocolate fudge frosting, lunch lady peanut butter bars are a classic childhood favorite! You’re going to love them!

Prep Time20 MINUTES

Cook Time15 MINUTES

Crust Chill30 MINUTES

Total Time1 HOUR 5 MINUTES



  • 1 cup salted butter softened
  • 1 cup granulated sugar
  • 1 cup brown sugar firmly packed
  • 1 cup peanut butter
  • 2 large eggs
  • 1 teaspoon vanilla extract
  • 2 cups old fashioned rolled oats
  • 2 cups all-purpose flour
  • 1 teaspoon baking soda
  • 1 teaspoon salt

Peanut Butter Fudge Layer

  • 1 1/2 cups peanut butter
  • 1/2 cup powdered sugar
  • 1/4 cup salted butter melted

Chocolate Frosting

  • 1 cup salted butter softened
  • 1/4 cup milk
  • 1/3 cup heavy cream
  • 1/2 cup cocoa powder
  • 5 cups powdered sugar


  • Preheat oven to 350 degrees Fahrenheit and grease an 18×13 baking sheet with non-stick spray.


  • In a large bowl or upright stand mixer, cream together butter, sugar, and brown sugar.
  • Add peanut butter, eggs, and vanilla. Mix to combine.
  • Add oats, flour, baking soda, and salt, and mix until well combined.
  • Add the dough to the greased baking sheet and bake for 14-16 minutes.

Peanut Butter Fudge Layer

  • In a bowl combine powdered sugar, and melted butter. Mix until smooth.
  • Add in peanut butter and mix until smooth.
  • Once crust is cooked and while still warm, drop spoonfuls of the peanut butter fudge across the warm crust. Let melt a bit then spread across the crust. Let cool completely.

Chocolate Frosting

  • Mix all ingredients together with a hand mixer or upright stand mixer until combined, smooth, and a bit fluffy, about 3-4 minutes.
  • Spread frosting onto cooled peanut butter fudge layer. Slice into bars and enjoy!

Lunchroom Chocolate Peanut Butter Bars.

Prep Time20 MINUTES

Cook Time20 MINUTES

Cooling Time1 HOUR

Total Time1 HOUR 40 MINUTES

Servings: 24 bars

Calories Per Serving: 253 kcal

Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.


  • ▢1 1/2 sticks (3/4 cup) salted butter
  • ▢2 cups creamy peanut butter
  • ▢3/4 cup light brown sugar
  • ▢1/4 cup granulated sugar
  • ▢2 large eggs, at room temperature
  • ▢1 tablespoon vanilla extract
  • ▢2 cups all-purpose flour
  • ▢1 teaspoon baking powder
  • ▢1/2 teaspoon kosher salt


  • ▢1 stick (1/2 cup) salted butter, at room temperature
  • ▢2-3 cups powdered sugar
  • ▢1/2 cup cocoa powder
  • ▢2 teaspoons vanilla extract
  • ▢1/4 cup warmed milk


  • 1. Preheat the oven to 350 degrees F. Line a 9×13 inch baking dish with parchment paper.2. In a microwave safe bowl, melt together the butter and 1/2 cup peanut butter, stirring every 30 seconds until melted. Stir in the brown sugar, sugar, eggs, and vanilla. Add the flour, baking powder, and salt.3. Press/spread the dough out into the prepared dish. Transfer to the oven and bake for 18-22 minutes, until just set in the center. Remove from the oven and dollop tablespoon size spoonfuls of the peanut butter over the bars, lightly spreading the peanut butter in an even layer. Let cool completely.4. To make the frosting. Add the butter, 2 cups powdered sugar, cocoa powder, vanilla, and 1/4 cup warm milk to the bowl of a stand mixer. Beat until smooth, adding additional warm milk until the frosting becomes thicker, but still drizzly. Taste, adding more sugar if needed. Spread the frosting over the bars. Let set for 1-ish hour…or slice, snack, and enjoy!


To Make Gluten Free: Use an equal amount of your favorite gluten free flour blend in place of the all-purpose flour.

Storing: these bars keep well for 3-4 days at room temperature or in the fridge. 

To cool the bars quickly for frosting: place in freezer for 15 minutes. Remove and frost.

To Bring Eggs to Room Temperature: place the eggs in a bowl and fill with warm water. Let sit 5 minutes.

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