These Peanut Butter Bars with oatmeal are a soft, chewy baked cookie bar topped with an extra layer of peanut butter and a rich chocolate frosting. Ideal for parties and potlucks—this recipe makes a large pan so it serves a crowd.
This recipe is nostalgic for many—often served in school cafeterias as “Peanut Butter Fingers,” they were traditionally cut into long, thin rectangles. The bars below are shown cut into squares, but the flavor and texture remain the same.
They’re a perfect crowd-pleaser because the recipe yields a lot and the peanut butter + chocolate combo is universally loved—kids and adults alike. If you have a peanut allergy, of course these aren’t for you, but otherwise expect them to disappear fast at any gathering.
Peanut Butter Bars with Oatmeal
These are more than simple peanut butter cookie bars—old fashioned oats in the dough add a pleasantly chewy texture. While the bars are still warm, a thin layer of peanut butter is spread on top, and then everything is finished with a smooth, chocolate frosting.
For a darker, richer chocolate frosting you can use a special dark cocoa, though regular unsweetened cocoa works fine as well. The frosting is simple to make and can be decorated with a light bakery swirl for an attractive finish.
These bars are easy to make, travel well, and are guaranteed to be a hit at potlucks and parties. If you prefer a no-bake option for hot weather, consider a chilled peanut butter bar alternative.
Peanut Butter Bars
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Ingredients
- ½ cup (113 g) unsalted butter, (1 stick) softened
- 1 cup (200 g) granulated sugar
- 1 cup (200 g) brown sugar, gently packed
- 2 large eggs
- 2 tsp vanilla extract
- 1 cup (264 g) creamy peanut butter
- 1 ¾ cups (219 g) all-purpose flour, (stir, spoon, & level)
- 2 cups (160 g) old fashioned oats
- 1 tsp baking soda
- ½ tsp salt
Frosting:
- 1 cup (264 g) creamy peanut butter, divided
- ½ cup (113 g) unsalted butter, (1 stick) very soft
- 3 cups (360 g) powdered sugar
- ¼ cup (20 g) unsweetened cocoa powder, (I use Hershey’s Special Dark)
- 1 tsp vanilla extract
- 3 Tbsp milk
Instructions
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Preheat the oven to 350°F. Lightly grease a 12×18-inch jelly roll or rimmed half-sheet pan with cooking spray.
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For the bars: In a stand mixer fitted with the paddle attachment, cream the softened butter with the granulated and brown sugars until light and fluffy. Add the eggs and vanilla and mix well, then stir in the peanut butter. Scrape down the bowl as needed.
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In a separate bowl whisk together the flour, oats, baking soda, and salt. Gradually add the dry ingredients to the mixer and blend until incorporated.
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Press the dough evenly into the prepared pan. Tip: A lightly floured rolling pin helps to distribute and flatten the dough for an even layer.
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Bake at 350°F for 12–15 minutes. Do not overbake. Remove from the oven and let rest for 3 minutes.
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While the bars are still warm, drop dollops of 1 cup peanut butter over the top and use an offset spatula to spread it into a thin, even layer. Let the peanut butter set—place the pan in the refrigerator or freezer briefly to speed this up if needed.
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To make the frosting: Beat the very soft butter until light and fluffy. Add the powdered sugar, cocoa powder, vanilla, and milk, and mix until smooth. Drop spoonfuls of frosting over the peanut butter layer and spread evenly. Create a bakery swirl design if you like. Once set, cut into bars and serve.
Notes
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