Peanut Butter Bars
This post may contain affiliate links. Read our disclosure policy.
Peanut Butter Bars are a childhood favorite! You get a chewy peanut butter oat cookie base, topped with a smooth layer of pure peanut butter, and a final layer of rich chocolate frosting. People of all ages love them!
This recipe is for the baked version of peanut butter bars, making a cookie-like bar rather than something more reminiscent of a candy bar.
They are a go-to dessert for celebrations and holiday parties. Not only are they beyond delicious but the recipe makes an entire cookie sheet full making them perfect for a crowd.
They always disappear in no time because who doesn’t love the chocolate and peanut butter combo, and who doesn’t love cookies plus frosting?
Some people know these as “lunch lady peanut butter bars” because they may be a nostalgic treat you grew up eating at school lunch. But trust, this version is much better!
You’ll find they have an abundance of rich peanut butter flavor, complimented by the decadence of chocolate to highlight them, along with a perfect balance of sweetness. The various layer of textures are melt in your mouth buttery, rich meets creamy, plus soft and chewy and it’s such a satisfying blend.
I think it’s fair to say they really are one of the most tempting treats you can make and likely a recipe you’ll have on repeat!
Peanut Butter Cookie Bar Recipe Ingredients:
- All-purpose flour: This is the staple ingredient for the structure of the cookies.
- Quick oats: Oats add more structure, a great texture and a nice flavor that compliments peanut butter.
- Baking soda: A leavening agent that helps the bars rise.
- Brown sugar, granulated sugar and powdered sugar:
- Salt: Added to balance the sweetness.
- Unsalted butter: A key ingredient to moisten the cookie bars.
- Eggs: These act as a binder holding ingredients together. to bind
- Creamy peanut butter: Adds lots of flavor and richness to the cookies.
- Vanilla: A flavor enhancer for baking.
- Cocoa powder: This gives the frosting it’s rich chocolate flavor and deep color.
- Milk: Used to thin the frosting to a spreadable consistency.
How to Make Peanut Butter Bars:
Even though these have several layers these really are a breeze to make.
Heat oven prepare pan: Preheat oven to 350 degrees. Butter a rimmed 18 by 13-inch cookie sheet.
Mix dry ingredients: In a mixing bowl whisk together flour, oats, baking soda and salt. Set aside.
Cream butter and sugars: In the bowl of an electric stand mixer fitted with the paddle attachment, blend together butter, brown sugar and granulated sugar until creamy.
Blend in eggs: Add one egg and blend to combine, then blend in second egg.
Cream in p.b. and vanilla: Blend in 1 cup peanut butter and the vanilla.
Add dry ingredients: Add in flour mixture and mix on low speed just until combined.
Spread dough onto cookie sheet: Drop cookie dough onto prepared baking sheet. Spray hands with non-stick cooking spray and spread dough into an even layer.
Bake nearly through: Bake in preheated oven 13 – 15 minutes until golden.
Top with peanut butter: Remove from oven and cool 5 minutes, then dollop remaining 1 cup peanut butter by spoonfuls over top. Let sit 1 minute then spread peanut butter into an even layer to cover top.
Make frosting: Melt butter in a medium saucepan. Stir in cocoa, milk and salt and bring mixture just to a boil over medium heat.
Remove from heat and whisk in vanilla, then stir in powdered sugar and mix until well combined (if needed you can add 1 Tbsp hot water to thin).
Top with frosting: Immediately pour over bars and spread into an even layer. Allow frosting to set then cut into squares. Store in an airtight container.
Tips for the Best Homemade Peanut Butter Bars
- Use creamy peanut butter only: Don’t use crunchy peanut butter or natural peanut butter for the recipe or the consistency of the cookie bars won’t turn out quite the same.
- Be mindful of continued “cooking” from residual heat: Be careful not to over bake these or the edges will be dry. Plus they’ll continue to cook just a little once removed from the oven from the heat of the baking sheet. They should still appear slightly under baked in the center when you remove them from the oven.
- Add peanut butter layer shortly after baking: Add peanut butter atop warm cookie bars so it melts nicely and sort of absorbs into the cookies a little.
Storage and Shelf Life
- Peanut butter bars will keep well stored in an airtight container at room temperature for 3 days.
- You can just cover the bars with plastic wrap or aluminum foil rather than transferring for room temperature storage.
- For freezer storage cut into bars and chill through in fridge first (or flash freeze) so the frosting sets. Layer into a storage container with parchment paper between layers and freeze in an airtight container up to 3 months.
More Peanut Butter Recipes You’ll Love!
- Classic Peanut Butter Cookies
- Crisp Peanut Butter Crinkle Cookies
- No Bake Cookies
- Peanut Butter Blossoms
- Peanut Butter Fruit Dip
Follow Cooking Classy
Peanut Butter Bars
Ingredients
- 2 cups (283g) all-purpose flour
- 2 cups (181g) quick oats
- 1 tsp baking soda
- 1/4 tsp salt
- 1 cup (226g) unsalted butter, softened
- 1 1/4 cups (250g) packed light-brown sugar
- 3/4 cup (150g) granulated sugar
- 2 large eggs
- 1 cup (250g) creamy peanut butter
- 1 tsp vanilla extract
Frosting
- 1 cup (250g) creamy peanut butter
- 1/2 cup 113g) unsalted butter, diced into 1 Tbsp pieces
- 1/4 cup (26g) unsweetened cocoa powder
- 1/4 cup (60g) milk
- 2 pinches salt
- 1 tsp vanilla extract
- 3 cups (360g) powdered sugar
Instructions
- Preheat oven to 350 degrees. Spray a rimmed 18 by 13-inch cookie sheet with non-stick cooking spray.
- In a mixing bowl whisk together flour, oats, baking soda and salt. Set aside.
- In the bowl of an electric stand mixer fitted with the paddle attachment, blend together butter, brown sugar and granulated sugar until creamy.
- Mix in eggs one at a time. Then blend in 1 cup peanut butter and the vanilla.
- Add in flour mixture and mix just until combined.
- Drop cookie dough onto prepared baking sheet. Spray hands with non-stick cooking spray and spread dough into an even layer.
- Bake in preheated oven 13 - 15 minutes until golden (see notes).
- Remove from oven and cool 5 minutes, then dollop remaining 1 cup peanut butter by spoonfuls over top. Let sit 1 minute then spread peanut butter into an even layer to cover top.
- Melt butter in a medium saucepan. Stir in cocoa, milk and salt and bring mixture just to a boil over medium heat.
- Remove from heat and whisk in vanilla, then stir in powdered sugar and mix until well combined (if needed you can add 1 Tbsp hot water to thin).
- Immediately pour over bars and spread into an even layer. Allow frosting to set then cut into squares. Store in an airtight container.
Notes
- Be careful not to over-bake or edges will be dry, don't wait for it to be golden brown. They should be puffed and beginning to set but still soft.
- Recipe adapted from Taste of Home