Peanut Butter Lunch Lady Cookie Bars

I’ve always loved those old-school cafeteria treats, and this pan-sized version is perfect when you need something sweet for a crowd. Whether it’s a potluck, church social, or game night, these bars disappear fast and don’t require any fancy fussing.

I’m usually the one who brings dessert to our local meetup group, and a batch like this keeps everyone happy without me baking multiple trays. It’s rich, peanut-buttery, and absolutely not diet food—just the way a nostalgic treat should be.

Ingredients

Cookie Bar Base

• 2 cups all-purpose flour
• 2 cups granulated sugar
• 1 teaspoon baking soda
• 1 teaspoon salt
• ½ cup milk
• 1 teaspoon vanilla extract
• 2 large eggs, lightly beaten
• 1 ½ cups peanut butter, divided
• 1 ½ cups (3 sticks) unsalted butter, softened
• 2 tablespoons additional milk

Frosting

• ½ cup peanut butter
• 1 stick unsalted butter
• 2 tablespoons milk
• 4 cups powdered sugar

Instructions

Bake the Bars

1. Preheat your oven to 400°F. Grease a large rimmed cookie sheet or cover it with parchment.
2. In a mixing bowl, stir together the flour, sugar, baking soda, and salt. Set aside.
3. In another bowl or large measuring cup, whisk the ½ cup milk with the vanilla and eggs.
4. In a saucepan over medium heat, melt 1 cup (2 sticks) of the butter with 1 cup of the peanut butter. Let it come just to a boil, then remove from the heat.
5. Stir the flour mixture into the warm peanut butter mixture. Once mostly combined, add the egg and milk mixture and mix until smooth.
6. Spread the batter evenly onto the prepared cookie sheet, all the way to the edges.
7. Bake for about 20 minutes, or until a toothpick comes out clean from the center. Let the bars cool completely before frosting.

Make the Frosting

1. In a clean saucepan, melt the remaining stick of butter with the remaining ½ cup peanut butter and bring just to a boil.
2. Stir in the 2 tablespoons of milk, then gradually mix in the powdered sugar until the frosting is smooth and spreadable.
3. Pour or spread the frosting over the cooled bars, making sure to cover the surface evenly.
4. Allow the frosting to set before slicing and serving.