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Peanut Butter Lunch Lady Bars

If you've ever reminisced about those nostalgic school cafeteria desserts, you're going to fall head over heels for these Peanut Butter Lunch Lady Bars. They combine a chewy oatmeal cookie base with an indulgent peanut butter frosting for a sweet-salty treat that takes you right back to childhood.
Print Recipe Pin Recipe
Prep Time 15 minutes
Cook Time 18 minutes
Total Time 33 minutes
Servings: 4 servings
Course: Dessert
Cuisine: American
Ingredients Equipment Method Notes

Ingredients
  

For the Bars:
  • 1 cup (2 sticks) unsalted butter softened
  • 1 cup creamy peanut butter
  • 1 cup granulated sugar
  • 1 cup packed light brown sugar
  • 2 large eggs
  • 1 teaspoon pure vanilla extract
  • 2 cups all-purpose flour
  • 1 teaspoon baking soda
  • ½ teaspoon salt
  • 2 cups quick oats
For the Frosting:
  • ½ cup creamy peanut butter
  • 4 tablespoons unsalted butter softened
  • 2 teaspoons vanilla extract
  • 3-4 tablespoons milk as needed for desired consistency
  • 2 cups powdered sugar

Equipment

  • 10×15-inch Jelly Roll Pan
  • Mixing bowls
  • Electric mixer
  • Spatula

Method
 

  1. Preheat your oven to 350°F (175°C). Grease a 10×15-inch jelly roll pan or line it with parchment paper.
  2. For the bars, cream together 1 cup (2 sticks) softened unsalted butter with 1 cup creamy peanut butter until smooth. Then add the granulated sugar and packed light brown sugar, beating until the mixture becomes fluffy and light in color.
  3. Beat in 2 large eggs one at a time, ensuring each is fully incorporated. Stir in 1 teaspoon of pure vanilla extract.
  4. In a separate bowl, whisk together 2 cups all-purpose flour, 1 teaspoon baking soda, and ½ teaspoon salt. Gradually add the dry ingredients to the butter-peanut butter mixture, mixing just until combined.
  5. Gently fold in 2 cups of quick oats until evenly distributed. The batter will be thick and somewhat sticky.
  6. Spread the batter evenly in your prepared pan, ensuring it is pressed into the corners.
  7. Bake for 15-18 minutes, or until the edges turn golden and the center is mostly set but still soft.
  8. While the bars cool slightly, prepare the frosting by creaming together ½ cup creamy peanut butter and 4 tablespoons softened unsalted butter until smooth. Stir in 2 teaspoons vanilla extract.
  9. Gradually mix in 2 cups powdered sugar. Add 3-4 tablespoons milk as needed to achieve a thick but spreadable consistency.
  10. Spread the frosting over the warm bars so it melts slightly into the top, then allow the bars to cool completely before cutting into squares.

Notes

These Peanut Butter Lunch Lady Bars are nostalgic treats made with simple, pantry-friendly ingredients. The recipe yields a chewy oatmeal-peanut butter base topped with a creamy frosting that melts slightly into the warm bars, creating a signature finish. For variations, try swapping in almond or sunflower seed butter for a twist or mix in mini chocolate chips for extra decadence. Serve with a scoop of vanilla ice cream, cold milk, or even a hot cup of coffee for the perfect dessert experience.