Peanut Butter Cookie Bars

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These peanut butter cookie bars are easy to make in under 30 minutes. They are gooey, chewy and loaded with peanut butter!

3 Peanut Butter Cookie Bars, one with a bite taken out of it


Sometimes the craving for peanut butter cookies strikes, but I don’t want to have to wait for the dough to chill or roll and bake multiple batches of cookies – so I make these peanut butter cookie bars instead!

These peanut butter cookie bars are soft, buttery and absolutely loaded with peanut butter. Ready from start to finish in 30 minutes – they are everything you love about your favorite cookie with a fraction of the work!

Make them your own by adding your favorite mix-ins like chocolate chips or peanut butter chips!

a stack of 4 Peanut Butter Cookie Bars, the top one has a bite taken out of it
overhead view of the ingredients in this Peanut Butter Cookie Bars recipe
  • Salted Butter. Unsalted butter or ghee are good substitutes.
  • Creamy Peanut Butter. Choose your favorite creamy peanut butter. Just be aware of the salt content. If using unsalted peanut butter, increase the salt by 1/4 teaspoon.
  • Whole Milk. 2% milk, heavy cream or half and half are good substitutes.
  • Light Brown Sugar. If you like a little bolder, molasses taste then you can use dark brown sugar.
  • Granulated Sugar. White sugar or organic cane sugar are both great options.
  • Sea salt. I only ever bake with pure, fine sea salt. If you are using iodized salt I recommend decreasing the amount of salt by half.
  • Peanut butter chips. You can omit these, or choose a different mix-in such as chocolate chips, cinnamon chips, etc.
16 Peanut Butter Cookie Bars cut into squares

Let’s walk through this peanut butter cookie bars recipe step-by-step, and don’t forget to watch the video.

Begin by mixing together flour, baking soda, salt, baking powder cinnamon in a medium bowl, then set it aside.

two photos showing how to make Peanut Butter Cookie Bars - mixing dry ingredients

Then, in the bowl of a standing mixer fitted with the paddle attachment, or in a large bowl with a hand-held mixer, cream together butter and peanut butter until smooth.

two photos showing how to make Peanut Butter Cookie Bars -  beating butter and peanut butter

Next, add the sugars and beat until combined.

two photos showing how to make Peanut Butter Cookie Bars - adding sugars

Then, add the egg, vanilla and milk and beat for 30-60 seconds on medium-high speed until the mixture is light in color and sugar is dissolved.

two photos showing how to make Peanut Butter Cookie Bars - adding egg, vanilla and milk

Once the mixture is smooth, add the dry ingredients and mix on low speed until combined.

two photos showing how to make Peanut Butter Cookie Bars - combining wet and dry ingredients

If you want to add some mix-ins, now is the time to do it! Add 1 cup of mix-ins into the dough and stir to combine. Here are some suggestions:

  • chocolate chips
  • peanut butter chips
  • cinnamon chips
  • chopped peanuts
  • mini peanut butter cups
  • Reese’s pieces 
two photos showing how to make Peanut Butter Cookie Bars - adding peanut butter chips

Press the dough evenly into the prepared baking dish, then bake in preheated oven for approximately 22-25 minutes until the top is lightly browned.

Let the bars cool in a wire rack (note, they will likely “deflate” a little bit as they cool, that is normal).

peanut butter cookie bars in the pan before and after baking

Cool, Cut & Serve

Finally, let the peanut butter cookie bars cool for at least 60 minutes. The longer they cool, the better they hold up to cutting.

If you’re just going to serve them warm with vanilla ice cream, then I wouldn’t worry too much about their appearance, because the taste and warm gooey texture is most important in that situation! 

16 Peanut Butter Cookie Bars cut into squares

Store/Freeze

Store these peanut butter cookie bars in an airtight container in the refrigerator for up to 1 week, or in the freezer for up to 2 months. 

a Peanut Butter Cookie Bar with a bite taken out of it
Can I double this recipe? 

Yes, double the ingredients and bake the bars in a 9×13″ baking dish for 25 minutes (or until the edges are golden brown and the top is lightly browned and set). 

How many bars does a 9×13 pan hold?

If you double this recipe and make it in a 9×13″ pan, you can make up to 36 bars, depending on the size you cut them. 

Do cookie bars harden as they cool?

Yes, they harden as they cool or are stored in the refrigerator.

Can I use natural peanut butter in this recipe?

Yes. Natural peanut butter (with 2 ingredients: peanuts and salt) works well in this recipe. You can also use this homemade peanut butter.

How do you cut bar cookies cleanly and evenly?

If you’re cutting these to add to a cookie tray or serve to a crowd, here are my tips on getting clean, even squares:
Let the bars cool all completely to room temperature before cutting. 
Use a very sharp, long knife. 
Dip the knife in warm water and quickly dry it off before the first cut. Then wipe it clean, dip it in warm water, then dry again before each subsequent cut. 
Use a ruler to measure equal pieces. If cutting these cookie bars into 16 squares, you’d want each bar to be 2″ x 2.”

How do you know when peanut butter cookie bars are done?

They are done when the edges are lightly golden brown and the top is set. They will jiggle slightly when removed from the oven, which gives you the nice gooey center pieces. If you prefer a firmer cookie bar, bake longer. 

a Peanut Butter Cookie Bar with a bite taken out of it

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Peanut Butter Cookie Bars

Laura
These peanut butter cookie bars are easy to make in under 30 minutes. They are gooey, chewy and loaded with peanut butter!
5 from 5 votes
Course cookies, Dessert
Cuisine American
Servings 16 Bars
Calories 231
Prep Time5 minutes
Cook Time22 minutes
Cooling1 hour
Total Time1 hour 27 minutes

Ingredients 
 

Instructions 

  • Preheat oven to 350 degrees F. Line a 9×9” baking pan with parchment paper and set aside.
  • In a medium bowl, mix together flour, baking soda, salt, baking powder cinnamon. Set aside.
  • Then, in the bowl of a standing mixer fitted with the paddle attachment, or in a large bowl with a hand-held mixer, cream together butter and peanut butter until smooth.
  • Add the granulated sugar and brown sugar and beat until combined.
  • Add egg, vanilla and milk and beat for 30-60 seconds on medium-high speed until the mixture is light in color and sugar is dissolved.
  • Add the dry ingredients and mix on low speed until combined.
  • If desired, add peanut butter chips or desired mix-ins and stir until combined.
  • Press the dough evenly into the prepared baking dish, then bake in preheated oven for approximately 22-25 minutes until the top is lightly browned.
  • Let the bars cool in a wire rack (note, they will likely “deflate” a little bit as they cool, that is normal).
  • Once cooled, cut into 9 or 16 squares and serve.

Video

Notes

Ingredient Substitutions
  • Salted Butter. Unsalted butter or ghee are good substitutes.
  • Creamy Peanut Butter. Choose your favorite creamy peanut butter. Just be aware of the salt content. If using unsalted peanut butter, increase the salt by 1/4 teaspoon.
  • Whole Milk. 2% milk, heavy cream or half and half are good substitutes.
  • Light Brown Sugar. If you like a little bolder, molasses taste then you can use dark brown sugar.
  • Granulated Sugar. White sugar or organic cane sugar are both great options.
  • Sea salt. I only ever bake with pure, fine sea salt. If you are using iodized salt I recommend decreasing the amount of salt by half.
  • Peanut butter chips. You can omit these, or choose a different mix-in such as chocolate chips, cinnamon chips, etc.
Store/freeze
Store these peanut butter cookie bars in an airtight container in the refrigerator for up to 1 week, or in the freezer for up to 2 months. 

Nutrition

Serving: 1bar | Calories: 231kcal | Carbohydrates: 23g | Protein: 5g | Fat: 14g | Saturated Fat: 5g | Polyunsaturated Fat: 2g | Monounsaturated Fat: 6g | Trans Fat: 0.2g | Cholesterol: 26mg | Sodium: 192mg | Potassium: 122mg | Fiber: 1g | Sugar: 15g | Vitamin A: 194IU | Vitamin C: 0.001mg | Calcium: 22mg | Iron: 1mg

Nutrition information is automatically calculated, so should only be used as an approximation.

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Recipe Rating




6 Comments

  1. 5 stars
    These are so delicious! Were a little crumbly when warm but firmed up when I decided to be patient and let them cool! Added a few Reese’s pieces 😀

  2. 5 stars
    Scrumptious! These are exactly what I was hoping for. Great texture, sweet & peanut buttery. Plus so easy to make (I used a whisk instead of a mixer & self rising flour with a touch of cinnamon). Can’t wait to make these for a family get-together! Only downside is having to share….lol