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A tray of freshly baked Peanut Butter Lunch Lady Bars with a thick, fudgy chocolate frosting, cut into perfect squares.
Lady Maria

Peanut Butter Lunch Lady Bars

These Peanut Butter Lunch Lady Bars are a nostalgic treat featuring a soft, chewy peanut butter base and a thick, creamy peanut butter frosting. Unapologetically rich and satisfying, this simple recipe delivers pure comfort in every square, reminiscent of classic schoolhouse cafeteria desserts.
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Prep Time 20 minutes
Cook Time 25 minutes
Total Time 45 minutes
Servings: 24
Course: Dessert, Snack
Cuisine: American
Calories: 350
Ingredients Equipment Method Notes

Ingredients
  

  • For the Peanut Butter Base:
  • 1 cup unsalted butter, softened to room temperature
  • 1 cup creamy peanut butter
  • 1 cup packed light brown sugar
  • 1/2 cup granulated sugar
  • 2 large eggs, at room temperature
  • 2 teaspoons vanilla extract
  • 2 cups all-purpose flour
  • 1 teaspoon baking soda
  • 1/2 teaspoon salt
  • For the Peanut Butter Frosting:
  • 1/2 cup unsalted butter, softened to room temperature
  • 1 cup creamy peanut butter
  • 2 cups powdered sugar, sifted
  • 3 to 4 tablespoons milk or heavy cream
  • 1 teaspoon vanilla extract

Equipment

  • 9x13 inch baking pan
  • parchment paper
  • Stand mixer or hand mixer
  • Large mixing bowl
  • Medium mixing bowl
  • Spatula
  • offset spatula
  • whisk
  • Measuring cups
  • Measuring spoons
  • wire cooling rack

Method
 

  1. Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking pan and line it with parchment paper, leaving an overhang on two sides to use as handles.
  2. In a large bowl with a mixer, beat the softened butter, 1 cup of creamy peanut butter, light brown sugar, and granulated sugar on medium-high speed for 2-3 minutes until light and fluffy.
  3. Add the eggs one at a time, beating well after each. Scrape down the sides of the bowl, then mix in 2 teaspoons of vanilla extract.
  4. In a separate medium bowl, whisk together the all-purpose flour, baking soda, and salt.
  5. With the mixer on low speed, gradually add the dry ingredients to the wet mixture, mixing only until just combined. Do not overmix.
  6. Transfer the thick dough to the prepared pan. Lightly grease your hands or a spatula to press the dough into an even layer.
  7. Bake for 20-25 minutes, until the edges are lightly golden and the center is set but still soft. A toothpick should come out with moist crumbs. Let the base cool on a wire rack for 15-20 minutes.
  8. While the base cools, prepare the frosting. In a large bowl, beat the 1/2 cup of softened butter and 1 cup of creamy peanut butter until smooth. Gradually mix in the powdered sugar on low speed.
  9. Add 1 teaspoon of vanilla and 3 tablespoons of milk. Increase mixer speed to medium-high and beat for 2-3 minutes until light and fluffy. Add another tablespoon of milk if the frosting is too thick.
  10. Spread the frosting evenly over the still-warm base using an offset spatula. The warmth will help it glide on smoothly.
  11. Allow the bars to cool completely at room temperature, or in the refrigerator for about 1 hour to set the frosting faster. Once set, use the parchment handles to lift the bars from the pan and cut into squares.

Notes

For the best texture, ensure your butter and eggs are at room temperature. Do not overbake the base; pull it from the oven when the center still looks slightly underdone. Let the bars cool completely before cutting to ensure clean slices. Store in an airtight container at room temperature for up to 4 days. For variations, try folding 1 cup of chocolate chips into the batter, sprinkling flaky sea salt over the finished frosting, or using crunchy peanut butter in the base for added texture.