A sweet throwback that never goes out of style.
There’s a reason school cafeteria recipes stick with us—they’re simple, satisfying, and made to please a crowd. These Peanut Butter Lunch Lady Cookie Bars are no exception. Inspired by those classic lunchroom desserts we all remember (and secretly loved), this version brings all the soft, salty-sweet goodness of the original… but better.
These cookie bars are baked in a sheet pan, which means no scooping, no chilling, and no rolling dough. Just spread the batter and bake—easy as that. The result? A batch of soft, rich peanut butter bars with a fudgy texture that’s more like a brownie than a traditional cookie.
And the frosting? Oh, the frosting. It’s a warm, silky peanut butter glaze that seeps into the top of the bars and sets with just the right amount of creamy sweetness. It’s honestly the kind of dessert that doesn’t last long—especially if you’ve got family or neighbors around.
Why These Bars Belong in Your Recipe Box
- One pan = less mess – Perfect for potlucks, parties, and bake sales.
- Full peanut butter flavor – In both the base and the frosting.
- Salty-sweet perfection – A balance that’s hard to beat.
- Feeds a crowd – Makes 16–24 bars.
- Make ahead – The texture only improves the next day!
Helpful Tips
- Don’t skip the parchment paper if you want easy removal and clean edges.
- Let the bars cool completely before pouring the warm frosting—this gives the top a glossy finish without melting into the cake.
- Want to change it up? Swap in chocolate frosting or sprinkle with chopped peanuts.
Peanut Butter Lunch Lady Cookie Bars
Yield: 16–24 bars
Prep Time: 15 minutes
Cook Time: 20 minutes
Total Time: 1 hour (includes cooling & frosting)
Ingredients
For the Bars:
- 2 cups all-purpose flour
- 2 cups granulated sugar
- 1 teaspoon baking soda
- 1 teaspoon salt
- ½ cup whole milk
- 1 teaspoon vanilla extract
- 2 large eggs, beaten
- 1 cup (2 sticks) unsalted butter
- 1 cup creamy peanut butter
For the Frosting:
- ½ cup (1 stick) unsalted butter
- ½ cup creamy peanut butter
- 2 tablespoons milk
- 4 cups powdered sugar
Instructions
- Preheat oven to 400°F. Grease a large sheet pan (roughly 13×18 inches) or line with parchment paper.
- Mix dry ingredients: In a large bowl, whisk together flour, sugar, baking soda, and salt. Set aside.
- Whisk wet ingredients: In a separate bowl, combine ½ cup milk, vanilla, and beaten eggs.
- Create the base: In a medium saucepan, melt 1 cup butter with 1 cup peanut butter over medium heat. Once it reaches a gentle boil, remove from heat.
- Combine: Slowly stir the dry ingredients into the melted peanut butter mixture. Then add the milk/egg mixture and stir until smooth and well mixed.
- Bake: Spread the batter evenly into the prepared pan. Bake for 20 minutes or until a toothpick inserted in the center comes out clean. Let cool completely in the pan.
- Make the frosting: In a small saucepan, melt ½ cup butter with ½ cup peanut butter. Bring just to a boil, then remove from heat. Stir in 2 tablespoons milk, then gradually mix in the powdered sugar until smooth.
- Frost the bars: Pour warm frosting over cooled bars and spread evenly. Allow to cool at room temperature until the frosting sets.
How to Store
- Room temperature: Keep covered for up to 3 days.
- Fridge: Lasts up to a week (let them come to room temp before serving).
- Freezer: Wrap tightly and freeze for up to 2 months. Thaw overnight.
