Peanut Butter Cookie Bars

5 from 1 vote

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!

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Prep Time15

Cook Time32

Total Time47

Servings: bars

Author: Molly Thompson

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 8x8-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.

Recipe Equipment

8x8-inch square baking pan (Note 1)

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.

Nutrition

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