It doesn't get any better than oatmeal chocolate peanut butter bars! To put it simply, they're the perfect cookie bar: soft and chewy, packed with oats and peanut butter, and stuffed with chocolate. This small batch recipe will satisfy your sweet tooth cravings, and it can be easily doubled to satisfy a crowd!
I think we're all in the mood for comfort food right now, and, for me, these soft and chewy cookie bars are just that. Peanut butter and chocolate are basically my happy place, and anything that feels like an upgraded chocolate chip cookie is exactly what I want to be baking.
Why This Recipe Works
Chewy and Peanut Buttery - These chocolate peanut butter oatmeal cookie bars are packed with peanut butter flavor and are super chewy thanks to oats, brown sugar, and egg yolk.
Stuffed with Chocolate (literally) - The cookie dough is full is chocolate chips AND there's a ribbon of rich chocolate filling running through the center of the bars!
Easy to Make - These easy cookie bars come together in just 30 minutes of hands on time and don't require any special kitchen equipment.
Small Batch - Since these cookie bars are truly indulgent, and since most of us are currently baking for only ourselves or our households, I designed this small batch recipe to make just 8 cookie bars.
Easy to Double - If just one bite of this small batch recipe already has you craving more, don't panic! The recipe can be easily doubled for even more peanut buttery oatmeal goodness. A doubled recipe can be baked in an 8x8 pan (see Recipe Notes for more information).
Fun Fact: Almost any bar recipe (brownies, cookie bars, etc.) that's baked in an 8 inch x 8 inch pan can be cut in half and baked in a loaf pan. Instant small batch recipe! A standard loaf pan is 8.5 inches x 4.5 inches, which is just slightly larger than half the area of an 8x8 pan. I baked these chocolate peanut butter oatmeal cookie bars in a loaf pan in order to have just 8 reasonably-sized bars. To learn more, read all about scaling down recipes for small batch baking.
Ingredient Notes & Substitutions
Old-Fashioned Oats - Be sure to use old-fashioned rolled oats, rather than quick oats, for this recipe. Quick oats absorb moisture more quickly and aren't ideal for baking.
Peanut Butter - I used traditional, creamy peanut butter in this recipe and have not tested the recipe using natural peanut butter.
Egg Yolk - An egg yolk helps to bind the dough together while creating a chewy cookie bar.
See recipe card at the bottom of this post for full ingredient list and measurements.
Step-By-Step Recipe Instructions
Step 1: Make the dough. In a small bowl, whisk together flour, oats, baking powder, baking soda, and salt. Set aside.
Step 2: Combine melted butter, peanut butter, and brown sugar, stirring until blended and smooth. Add egg yolk and vanilla and whisk until combined.
Step 3: Add the flour mixture to the butter mixture, and fold in the dry ingredients just until combined. Add the chocolate chips and stir. Set the dough aside.
Step 4: Add the chocolate chips and peanut butter to a small, microwave-safe bowl. Carefully melt the mixture in the microwave, stirring frequently until smooth and glossy. Add the confectioners' sugar and stir to combine.
Step 5: Press half of the dough into a standard loaf pan lined with parchment paper. Spread the chocolate filling over the dough in an even layer. Sprinkle the remaining cookie dough over the chocolate filling so that it's completely covered. Sprinkle a few extra chocolate chips and a pinch of salt over the top.
Step 6: Bake at 350ºF for 20 minutes or until the edges are a light golden brown. Let the bars cool in the pan before slicing into 8 squares to serve.
See recipe card at the bottom of this post for detailed recipe instructions.
You'll want to line your loaf pan with parchment paper to ensure that the bars don't stick to the pan. I used the same method to line the loaf pan that I use for an 8x8 pan. Check out this post to learn my simple method for lining pans with parchment paper
When crumbling the cookie dough over the chocolate peanut butter filling, be sure to gently press the cookie dough crumbles lightly into the pan. You don't want to press them into a flat layer, but you do want to be sure the crumbles will stick together when baked.
Though it's of course optional, I like to sprinkle a few extra chocolate chips over the top (along with a pinch of salt) to create picture perfect bar cookies. It's the same trick that I use to make chocolate chip cookies look pretty.
Absolutely! This small batch cookie bar recipe can easily be doubled to make 16 bars. Double the ingredients and bake the bars in an 8 in. x 8 in. metal pan. You may need to add a couple of minutes to the baking time, so keep an eye on the bars when baking. If doubling the recipe, you can chose to use 1 whole egg or stick with 2 egg yolks for extra chewiness.
In short, no. Quick oats absorb liquids more readily than old-fashioned oats, so they will not produce a hearty and chewy cookie dough texture. Therefore, I do not recommend using quick oats in baking (unless the recipe specifically calls for it).
When cookie bars turn out dry, the two most likely culprits are that they ingredients were not measured correctly or that the bars were over baked. Too much flour or not enough wet ingredients can cause bars to become too firm when baked, so be sure to measure your ingredients properly. Also be careful not to over bake the bars, which will cause them to dry out.
Just like freezing brownies, cookies bars freeze well for a few months when properly sealed. Before placing the bars in the freezer, wrap the completely cooled bars tightly with plastic wrap before wrapping them with a layer of aluminum foil or sealing the wrapped bars in an airtight, freezer-safe plastic food storage bag or container. Bars that have been frozen should be left to thaw either in the fridge or at room temperature before eating.
Room Temperature: Store leftover bars in an airtight container at room temperature for up to 4 days.
Freezing: Once baked and fully cooled, bars can be sealed in an airtight container and frozen for up to 3 months.
More Bar Recipes
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Small Batch Oatmeal Chocolate Peanut Butter Bars
Oatmeal Peanut Butter Cookie Dough:
- 9 Tablespoons all-purpose flour
- ⅜ cup old-fashioned oats
- ¼ teaspoon baking powder
- 1 pinch baking soda
- 1 pinch fine sea salt (plus more for sprinkling on top)
- 4 Tablespoons unsalted butter, melted
- 3 Tablespoons creamy peanut butter
- ½ cup light brown sugar
- 1 egg yolk
- ½ teaspoon vanilla extract
- ½ cup semi-sweet chocolate chips (plus more for topping bars)
- ¼ cup semi-sweet chocolate chips
- ¼ cup creamy peanut butter
- ¼ cup confectioners' sugar
- Preheat the oven to 350ºF. Line a standard loaf pan (8.5 in. x 4.5 in.) with parchment paper and set aside.
Make the cookie dough.
- In a small bowl, whisk together flour, oats, baking powder, baking soda, and salt. Set aside.
- Melt butter in a large, microwave-safe bowl. Add peanut butter and brown sugar and stir until blended and smooth.
- Add egg yolk and vanilla to the butter mixture and whisk until combined.
- Add the flour mixture to the butter mixture, and fold in the dry ingredients just until combined.
- Add the chocolate chips and stir until evenly distributed throughout the dough. Set the dough aside.
Make the chocolate filling.
- Add the chocolate chips and peanut butter to a small, microwave-safe bowl. Melt the mixture in the microwave in 30 second increments on 50% power, stirring after each stint in the microwave until smooth and glossy.
- Add the confectioners' sugar and stir to combine.
Bake the bars.
- Press half of the dough into the prepared pan. Use an offset or mini spatula to spread the chocolate filling over the dough in an even layer. Break up the remaining cookie dough into small, blackberry-sized pieces and scatter them over the chocolate filling so that it's completely covered. Sprinkle a few extra chocolate chips and a pinch of salt over the top.
- Bake for 20 minutes or until the edges are a light golden brown and a toothpick inserted into the bars comes out with just a few moist crumbs. Let the bars cool in the pan on a wire rack before removing them from the pan. Slice into 8 squares to serve.