These peanut butter cookie bars are soft, chewy, and studded with both chocolate chips and peanut butter chips. They’re baked in a 9×13 inch pan, or halve the recipe for an 8×8 inch pan. 
Easy desserts are always welcome, and these peanut butter cookie bars are perfect when you have a jar of smooth peanut butter and crave something comforting. The bars bake up thick and chewy, with lots of peanut butter flavor and plenty of chocolate chips. Because they’re baked as a slab rather than dropped as individual cookies, you can add more mix-ins without worrying about the dough spreading too thin.
Soft, chewy peanut butter cookie bliss.
They’re Like Peanut Butter Cookies — But Easier
Cookie bars save time and mess: no sticky fingers, no dough chilling, and no scooping individual cookies. To make the batter, start by creaming the butter with both the brown and white sugars until smooth and lump-free. Add the smooth peanut butter next — use a commercial smooth peanut butter (the kind that stays emulsified, like common store brands) rather than a natural one that separates.
Beat in two eggs for tenderness and add vanilla extract. Then combine the dry ingredients: all-purpose flour, baking powder and salt. Accurate flour measurement is important to keep the bars from becoming dry — spoon the flour into a measuring cup and level it off.
Fold in the chocolate chips and peanut butter chips. You can swap or add other mix-ins like M&Ms, chopped peanut butter cups, or Reese’s Pieces if you prefer. 
Press the batter into a parchment-lined 9×13 inch pan, smooth the top, and bake until set.
Pro tip: Parchment can slide in a pan, making it hard to spread the batter. Lightly spray the pan with non-stick cooking spray before lining it with parchment — the spray helps keep the paper in place.
Baking Tips & Variations
- To make a smaller batch, halve the ingredients and bake in an 8×8 inch pan; baking time will be shorter (about 20–25 minutes).
- This recipe is formulated specifically for bars. If you want drop cookies instead, use a dedicated peanut butter cookie recipe to avoid cookies spreading too thin.
- Mix-ins are flexible: use chocolate chips, peanut butter chips, M&Ms, or Reese’s Pieces — whatever you like.
- You can frost the cooled bars with a peanut butter or chocolate buttercream for an extra-treat version.
Note: Compared to peanut butter blondies, these cookie bars are less gooey and slightly less sweet. Blondies are denser and more brownie-like, while these bars have a cookie-like, chewy texture.
If you enjoy these Peanut Butter Cookie Bars, you might also like other cookie-bar variations such as chocolate chip, snickerdoodle, or sugar cookie bars.
Peanut Butter Cookie Bars
Fiona Dowling
15
30
15 bars
Equipment
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9×13 inch (23×33 cm) pan
Ingredients
- 3/4 cup unsalted butter, softened
- 3/4 cup brown sugar, light or dark
- 3/4 cup white sugar
- 1 cup smooth peanut butter, do not use homemade or natural
- 2 large eggs
- 2 teaspoons vanilla extract
- 2 cups all-purpose flour
- 1 teaspoon baking powder
- 1/4 teaspoon salt
- 3/4 cup chocolate chips
- 3/4 cup peanut butter chips, or replace with more chocolate chips
Instructions
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Preheat the oven to 350°F (175°C).
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Lightly spray a 9×13 inch pan with non-stick cooking spray, then line it with parchment paper leaving an overhang. Greasing first helps the parchment stay in place.
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In a large bowl, beat together the butter, brown sugar, and white sugar until smooth and lump-free.
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Beat in the peanut butter until smooth, then add the eggs and vanilla and mix until combined.
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Reduce the mixer speed to low and mix in the flour, baking powder, and salt. Scrape down the bowl as needed.
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Stir in the chocolate chips and peanut butter chips.
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Spoon the batter into the prepared pan and smooth the top.
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Bake on the middle rack for about 30 minutes, or until a toothpick inserted into the center comes out clean or with a few crumbs. Depending on your oven, baking may take 25–35 minutes.
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Remove from the oven and cool the pan on a wire rack for at least 45 minutes. Cooling fully in the pan gives the cleanest slices.
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Lift the bars from the pan using the parchment overhang, place on a cutting board, and slice. Store cooled bars in an airtight container at room temperature for up to 4 days.
Notes
- Use a commercial smooth peanut butter (brands that do not separate) rather than natural or homemade peanut butter.
- Any chocolate chips or candies work as mix-ins — feel free to customize.
- For a smaller batch, halve the recipe and bake in an 8×8 inch pan for about 25 minutes.
- Leftovers keep in an airtight container at room temperature for up to 4 days. Freeze cooled bars for up to 2 months; thaw in the fridge and bring to room temperature before serving.
- Nutrition values are estimates, based on cutting the pan into 15 equal bars.