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Lunch lady peanut butter bars no-bake retro school cafeteria dessert ready in 15 minutes with 1 cup salted butter cubed 1 cup creamy Jif or Skippy peanut butter microwaved 50% power 30-second increments stirred smooth, 1 teaspoon vanilla added, 2 cups graham cracker crumbs 1.75 cups powdered sugar folded thick dough pressed parchment-lined 9x9 pan refrigerated, 1.5 cups milk or semisweet chocolate chips 2 teaspoons coconut oil microwaved 30-second intervals stirred smooth poured top offset spatula spread even layer, refrigerated 2 hours set sliced 16 squares served

Lunch Lady Peanut Butter Bars

Soft and chewy peanut butter oat bars baked in a 9x13 pan and topped with a thick creamy cocoa peanut butter frosting. The classic school cafeteria dessert bar made at home with simple pantry ingredients and no special equipment needed.
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Prep Time 15 minutes
Cook Time 22 minutes
Total Time 1 hour
Servings: 24 bars
Course: Dessert
Cuisine: American
Calories: 218
Ingredients Equipment Method Notes

Ingredients
  

  • 1/2 cup unsalted butter, softened
  • 1/2 cup granulated sugar
  • 1/2 cup packed light brown sugar
  • 1/2 cup creamy peanut butter commercial brand like Jif or Skippy
  • 2 large eggs, room temperature
  • 1 tsp vanilla extract
  • 1 cup all-purpose flour
  • 1 cup quick-cooking oats
  • 1/2 tsp baking soda
  • 1/4 tsp fine salt
  • 1/4 cup unsalted butter, softened for frosting
  • 1/4 cup creamy peanut butter for frosting
  • 2 tbsp unsweetened cocoa powder
  • 2 cups powdered sugar, sifted
  • 3-4 tbsp whole milk added gradually
  • 1/2 tsp vanilla extract for frosting
  • 1 pinch salt for frosting

Equipment

  • 9x13 Baking Pan
  • Hand mixer or stand mixer
  • Mixing bowls
  • Spatula

Method
 

  1. Preheat oven to 350°F. Grease or line a 9x13 baking pan with parchment.
  2. Beat softened butter, granulated sugar, and brown sugar on medium speed for 2 to 3 minutes until light and fluffy. Add peanut butter and beat to combine.
  3. Add eggs one at a time, mixing after each. Add vanilla and mix briefly.
  4. Whisk together flour, oats, baking soda, and salt in a separate bowl. Add to wet ingredients and mix on low until just combined.
  5. Press dough evenly into the prepared pan. Bake 18 to 22 minutes until set at the edges and barely underdone in the center. Cool completely.
  6. Beat frosting ingredients together, adding milk one tablespoon at a time until thick and spreadable. Spread evenly over cooled bars.
  7. Let frosting set 20 minutes at room temperature. Slice into rectangles and serve.

Notes

  • Use commercial creamy peanut butter in both the base and frosting - natural peanut butter produces a greasy, unstable result.
  • Do not overbake - bars should look slightly underdone in the center when pulled from the oven.
  • Cool bars completely before frosting or the topping will melt and become greasy.
  • Refrigerate before slicing for the cleanest cuts through the frosting layer.
  • Bars taste best on day two after the oat base has fully settled.