Do you love peanut butter and trying easy recipes? Then these dessert bars have your name written all over them! Peanut butter cookie bars are super easy to make and have the best texture. They are perfectly soft and chewy. You can add chocolate chips or m&m’s for some extra fun too!

stack of peanut butter cookie bars next to more bars and spoonful of peanut butter.

I love a good salty, sweet snack. Whenever you bake with peanut butter you are almost always guaranteed that flavor combo. These cookie bars are so satisfying. I like them plain, but if you’re feeling like you need a little something extra, try adding chocolate chips!

Why this recipe works

These bars use melted butter and creamy peanut butter for a soft, chewy consistency that melts in your mouth. The dough is quick and easy to make too! The recipe is versatile so you can add mix-ins such as chocolate chips, m&m’s or nuts!

Ingredient notes

peanut butter cookie bars ingredients in bowls labeled with text.
  • Peanut butter: Use no-stir creamy peanut butter. I prefer Skippy all natural peanut butter. Do not use peanut butter that has oil sitting on the top. It will cause the bars to become greasy and crumbly.
  • Butter: Use unsalted since the peanut butter is already adding additional salt. Allow the melted butter to cool a bit before making the dough.
  • Flour: I used all purpose flour, but I’m sure a gluten-free flour such as cup-4-cup would work in this recipe. I do not recommend nut flours as they would cause the bars to become dense to to their higher protein content.

Recipe variations

You can make peanut butter cookie bars with chocolate chips, M&M’s or nuts. Reese’s pieces or peanut butter chips would also be good! I suggest 3/4 cup of whatever mix-in you choose. Stir them in by hand once the the dough is made. Another option is to add chocolate frosting on top of the bars after they have cooled.

photo collage demonstrating how to make peanut butter cookie bars in a mixing bowl and square pan.
  1. Whisk together the dry ingredients: flour, baking soda and salt. Set aside.
  2. Mix together melted butter and peanut butter until smooth, then add the brown sugar and sugar. Beat until well combined. Add the egg and vanilla and mix until incorporated.
  3. Add the dry ingredients to the wet ingredients and mix just until combined.
  4. Transfer dough to 8×8 baking pan lined with parchment paper. Press dough down into an even layer. Bake at 350 F for 20 to 22 minutes.

Expert tips

Do not over-bake the bars. Trust me, you want the center a little under-baked in order for you to get the nice gooey, chewy texture. Also, let the bars cool completely. They need time to set so they aren’t messy when you cut into them.

If you don’t have a kitchen scale, here’s how to to easily measure peanut butter: Grease a measuring cup before adding peanut butter to it. That way when you dump the peanut butter in the mixing bowl it slides right out. You don’t have to scrape the measuring cup!

Frequently Asked Questions

Why are my bars crumbly?

The cookie bars were probably over-baked and therefore dry. Another reason is too much flour. Either use a kitchen scale or spoon a level your flour into a measuring cup (never pack it down).

What’s the best peanut butter for making cookie bars?

Creamy no-stir peanut butter is best for baking cookie bars and cookies. I use Skippy all natural peanut butter.

Can I use this recipe for a 9×13 baking pan?

Yes, double this recipe to make it in a 9×13 baking pan. Baking time will be around 35 minutes.

Can I make these bars without a mixer?

Yes, but you will need some arm strength! Mixing the peanut butter, butter and sugar together will take some time to get a smooth and well combined mixture.

peanut butter cookie bars piled on small wire cooling rack.

Did you love this recipe? Please leave a 5-star 🌟🌟🌟🌟🌟 rating in the recipe card below and if you REALLY loved it, consider leaving a comment further down the page.

peanut butter cookie bar with a bite.

Peanut Butter Cookie Bars

Peanut butter cookie bars are soft, chewy and super easy to make from scratch. You can also add chocolate chips, m&m's or nuts to the dough!
5 (6 ratings)

Ingredients

  • 2 cups (250 g) all-purpose flour
  • 1 teaspoon baking soda
  • ½ teaspoon salt
  • 6 Tablespoons (85 g) unsalted butter, melted and slightly cooled
  • ½ cup (130 g) creamy no-stir peanut butter
  • ¾ cup (150 g) packed light brown sugar
  • ¼ cup (50 g) granulated sugar
  • 1 teaspoon pure vanilla extract
  • 1 large egg, room temperature
  • ¾ cup chocolate chips, m&m's or nuts, (optional)

Instructions 

  • Preheat oven to 350° F. Line a 8×8-inch square baking pan with parchment paper. Set aside.
  • In a medium mixing bowl, whisk together the flour, baking soda and salt. Set aside.
  • In the bowl of a stand mixer (or using a hand mixer), combine melted butter with peanut butter until smooth, about 1 minute. Add brown sugar and granulated sugar and mix until well combined. Add vanilla and egg. Mix well, about 2 minutes.
  • With the mixer on low, slowly add dry ingredients. Mix just until combined. The dough should be soft and slightly crumbly (that’s okay). If adding mix-ins, stir them in by hand.
  • Place dough in prepared pan and press, smoothing out the top until dough is firm. Gently press into the dough.
  • Bake bars at 350° F for 20 to 22 minutes. Cool in pan for 10 minutes, then transfer onto a cooling rack to cool completely. Cut and serve.

Notes

Peanut butter: Use creamy no-stir peanut butter such as Skippy all natural peanut butter. I do not recommend peanut butter that is separated with oil.
9×13 baking pan: Double the recipe and increase baking time to 35 minutes.
Store cookie bars in an airtight container at room temperature for up to 5 days.
Freeze cookie bars for up to 1 month. Wrap bars in plastic wrap and store in a freezer bag or airtight container.
Serving: 1bar, Calories: 199kcal, Carbohydrates: 27g, Protein: 4g, Fat: 9g, Saturated Fat: 4g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 3g, Trans Fat: 0.2g, Cholesterol: 22mg, Sodium: 183mg, Potassium: 81mg, Fiber: 1g, Sugar: 14g, Vitamin A: 146IU, Calcium: 18mg, Iron: 1mg

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