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Lunch lady peanut butter bars no-bake retro school cafeteria dessert 15 minutes 9x9 pan — peanut butter base 1 cup salted butter cubed 1 cup creamy peanut butter microwave 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, chocolate topping 1.5 cups milk or semisweet chocolate chips 2 teaspoons coconut oil microwaved 30-second intervals stirred smooth poured offset spatula spread even layer refrigerated 2 hours firm set 16 squares sliced served

Lunch Lady Peanut Butter Bars

Soft, 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 recreated at home with simple pantry ingredients, one pan, 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: 214
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 Jif or Skippy recommended
  • 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, sifted
  • 2 cups powdered sugar, sifted
  • 3-4 tbsp whole milk, added gradually
  • 1/2 tsp vanilla extract for frosting
  • 1 pinch fine salt for frosting

Equipment

  • 9x13 Baking Pan
  • Hand Mixer or Stand Mixer
  • Mixing Bowls
  • Offset Spatula

Method
 

  1. Preheat oven to 350°F. Line or grease a 9x13 baking pan.
  2. Beat butter, both sugars on medium speed 2 to 3 minutes until pale and fluffy. Add peanut butter and beat 1 minute. Add eggs one at a time, then vanilla.
  3. Whisk flour, oats, baking soda, and salt. Add to wet mixture and mix on low until just combined.
  4. Press dough evenly into the pan. Bake 18 to 22 minutes until edges are set and center looks barely underdone. Cool completely.
  5. Beat frosting butter and peanut butter until smooth. Add cocoa, vanilla, then alternate powdered sugar and milk until thick and spreadable.
  6. Spread frosting over cooled bars in one direction. Chill 20 minutes, then slice into rectangles with a warm clean knife.

Notes

  • Use commercial creamy peanut butter - natural peanut butter produces cakey, greasy bars that don't hold together properly.
  • Pull bars from the oven when the center still looks slightly underdone - they firm up completely as they cool.
  • Cool bars fully before frosting or the butter in the frosting will melt and the topping will slide.
  • Chill before slicing for the cleanest cuts through the frosting layer.
  • Store at room temperature up to 4 days or freeze individually wrapped for up to 2 months.