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Peanut butter cookie bars are a classic peanut butter cookie in bar form. Tender and chewy on the inside, they have a slight crisp and golden brown color on the edges. Try them with a scoop of vanilla ice cream!

Do you love cookie bars? Try these s’mores cookie bars, chewy turtle cookie bars, or peppermint bark cookie bars next!

peanut butter cookie bars cut into sqaures
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Table of Contents

  • Delicious flavor: If you’re a peanut butter lover, this will quickly become one of your favorite recipes.
  • Easy dessert recipe: We love easy recipes around here. This recipe is done in a few simple steps, combining the wet ingredients with the dry ingredients, baking, and enjoying.

Do you love dessert bars? Try chai blondies, gluten-free lemon bars, or apple pie bars next.

Ingredients You need

Here are the simple ingredients for this easy peanut butter bars recipe. Jump down to the recipe card for exact measurements.

peanut butter cookie bar ingredients on a countertop
  • All-purpose Flour: Sub gluten-free flour if needed.
  • Baking soda: Check the expiration date on it and make sure it’s not older than 6 months.
  • Cornstarch: For an extra chewy texture!
  • Unsalted butter: Plant-based vegan butter works too.
  • Creamy no-stir peanut butter: Not drippy peanut butter with oil.
  • Light brown sugar: Dark brown sugar works too.
  • Granulated sugar: White sugar, organic cane sugar, or coconut sugar and any of its substitutes are all options.
  • Salt & vanilla: For flavor
  • Egg: Use room temperature to mix into the dough better.
  • Milk: Use any kind like skim milk, whole milk, or almond milk.
  • Peanut butter chips: I used Reese’s Pieces, but white chocolate chips, butterscotch chips, or chocolate chips work as well.

Want to make peanut butter chocolate chip bars? Swap the peanut butter chips for regular chocolate chips!

Here are the simple steps, with photos, to make this peanut butter cookie bars recipe. Jump to the recipe card for printable version.

flour, salt, baking soda, and cornstarch in a bowl

Step 1. Dry Ingredients: Whisk the flour, baking soda, cornstarch, and salt together in a large mixing bowl.

peanut butter cookie dough wet ingredients in a bowl

Step 2. Wet ingredients: Whisk melted butter, brown sugar, and granulated sugar together until smooth. Whisk in the vanilla, egg, egg yolk, and then the milk.

peanut butter cookie bar dough in a mixing bowl.

Step 3. Finish Cookie Dough: Pour the wet ingredients into the dry ingredients and mix together until combined. The dough will be very soft and thick.

peanut butter cookie dough with peanut butter chips in a bowl.

Step 4. Add Peanut Butter Chips: Fold in the peanut butter chips.

peanut butter cookie dough pressed into a square baking dish.

Step 5. Press into Dish: Transfer the dough to the baking dish and press it into all four corners of the pan.

fresh baked peanut butter cookie bars.

Step 6. Bake: Bake for 32-35 minutes or until lightly browned on the sides. Insert a toothpick into the center of the bars to test for doneness.

Add Some Chocolate!

Want to make chocolate peanut butter cookie bars? Use regular chocolate chips or dark chocolate chips for peanut butter chocolate chip cookie bars! You could even drizzle melted chocolate on top of the bars.

peanut butter cookie bars cut into squares

Recipe FAQs

Why are my peanut butter cookies dry?

There could be a number of reasons that your cookie bars turn out dry. Be careful not to overmix or overbake the bars, to use enough fat, and not to overdo it on the flour.

What happens if you put too much peanut butter in cookies?

Excessive peanut butter can make the cookie dough too soft and sticky, resulting in flat cookies. It can also make the cookies overly greasy, but can also make them dry and crumbly. Be sure to follow the recipe’s measurements to avoid these issues.

Do peanut butter cookies need to be refrigerated?

If you expect to finish the cookies within a few days, you can store them at room temperature in an airtight container. If you want to keep the cookies for more than a few days, you can store them in the refrigerator for up to a week.

Freezing and Storing Tips

To store: Store in an airtight container at room temperature for up to a week. You can make the cookie dough and chill it in the refrigerator for up to 3 days.

Freeze: Freeze the cookie dough for up to 3 months. After freezing, allow the dough to come to room temperature and continue baking. Baked cookie bars freeze well wrapped in plastic wrap for up to 3 months. Thaw peanut butter cookie bars overnight in the refrigerator and bring them to room temperature before serving.

3 peanut butter cookie bars stacked

More Peanut Butter Treats

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5 from 1 vote

Peanut Butter Cookie Bars

Prep: 15 minutes
Cook: 32 minutes
Total: 47 minutes
Peanut butter cookie bars are a classic peanut butter cookie in bar form. Tender and chewy on the inside, they have a slight crisp and golden brown color on the edges. Try them with a scoop of vanilla ice cream!
peanut butter cookie bars on parchment paper
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Molly Thompson

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Molly Thompson
Servings: 16 bars

Ingredients

  • 2 1/4 cups (281 g) all-purpose flour spooned and leveled (Note 2 Gluten-Free)
  • 1 teaspoon baking soda
  • 1 1/2 teaspoons cornstarch
  • ½ teaspoon kosher salt
  • 6 Tablespoons (85g) unsalted butter melted and slightly cooled (Note 3. Dairy-Free)
  • 2/3 cup (173g) creamy no-stir peanut butter
  • ¾ cup (150g) packed light brown sugar
  • ¼ cup (50g) granulated sugar
  • 1 teaspoon pure vanilla extract
  • 1 large egg + 1 egg yolk room temperature (Note 4)
  • 2 Tablespoons milk any kind
  • 1 cup peanut butter chips we used Reese’s chips

Instructions 

  • Preheat oven to 350°F. Line a square 8×8-inch pan with parchment paper, leaving an overhang on all sides to easily lift the bars out of the pan when cool.
  • Whisk the flour, baking soda, cornstarch, and salt together in a large bowl.
  • In a medium bowl, whisk the melted butter, peanut butter, brown sugar, and granulated sugar together until no brown sugar lumps remain and the mixture is smooth. Whisk in the vanilla, egg, egg yolk, and then the milk. The mixture will be thick.
  • Pour the wet ingredients into the dry ingredients and use a rubber spatula to mix together until combined. The dough will be very soft and thick. Fold in the peanut butter chips. The chips may not stick to the dough because of the melted butter, but do your best to evenly distribute them into the dough.
  • Transfer the dough to the prepared pan and press it into all four corners of the pan, smoothing out the top into an even layer.
  • Bake for 32-35 minutes or until lightly browned on the sides. Insert a toothpick into the center of the bars to test for doneness. If it comes out clean, the bars are done. Start checking for doneness around 30 minutes as every oven and baking pan varies and can affect the cook time.
  • Allow the bars to cool in the pan set on a wire rack for at least an hour. Use the parchment paper to remove the bars from the pan. Cut into 16 squares and serve. Store in an airtight container at room temperature for up to a week.
Last step! If you make this, please leave a review letting us know how it was!

Notes

Note 1. Baking Pan. I use this USA bakeware pan and love it. You can use a 9-inch square pan but the bars won’t be quite as thick and will take slightly less time to bake, 30-32 minutes.
Note 2. Gluten-Free. Use a 1:1 gluten-free flour. Our favorites are Bob’s Red Mill 1:1 Baking Flour or King Arthur’s Measure for Measure flour.
Note 3. Dairy-Free. Swap the butter for plant-based butter. We love and always use Myokos. You can find it in any local grocery store.
Note 4. Room Temperature. When working with melted butter especially, it’s important that other chilled ingredients are brought to room temperature. Cold eggs can chill the butter in the cookie dough (when it’s supposed to be melted), which impacts the final texture of the bars. Place the eggs in a dish and cover with warm water to bring the eggs to room temperature quickly.
Make Ahead & Freezing Instructions: You can make the cookie dough and chill it in the refrigerator for up to 3 days or freeze it for up to 3 months. After freezing, allow the dough to come to room temperature and continue baking. Baked cookie bars freeze well for up to 3 months. Thaw peanut butter cookie bars overnight in the refrigerator and bring them to room temperature before serving.
9×13 Pan: Double this recipe to fit into a 9×13-inch baking pan. The bars will take longer to cook through, about 40 minutes.

Video

Equipment

  • 8×8-inch square baking pan (Note 1)

Nutrition

Serving: 1bar | Calories: 307kcal | Carbohydrates: 35.6g | Protein: 3.4g | Fat: 17.1g | Cholesterol: 58mg | Sodium: 174.8mg | Fiber: 0.7g | Sugar: 17.2g | Vitamin A: 141.8IU | Vitamin C: 0mg

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

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5 from 1 vote

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Recipe Rating




2 Comments

  1. Bob says:

    5 stars
    I used your recipe and the peanut butter bars were fantastic. Everyone loves them.
    Please note, the instructions do NOT mention when to add the peanut butter. I added the PB after heating the butter and whisking the two sugars.

    Thanks for sharing your recipe.

    Reply
    1. Molly Thompson says:

      Thanks for calling that out, Bob! I updated the recipe. You were correct to add it with the butter and sugars! Glad you liked them:)

      Reply