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+ servings
three soft peanut butter bars with frosting, stacked on top of each other.
5 from 21 votes

Lunch Lady Peanut Butter Bars

Tasty Lunch Lady Peanut Butter Bars have a chewy peanut butter oat base, creamy peanut butter center, and rich chocolate buttercream topping.
Author Diana
Servings 24 Bars
Prep Time 20 minutes
Cook Time 20 minutes
Chilling Time 1 hour
Total Time 1 hour 40 minutes

Ingredients

Base:

  • 1 cup (225 g) unsalted butter melted
  • 1 cup (240 g) creamy peanut butter
  • 1 cup (200 g) granulated sugar
  • 1 cup (200 g) light brown sugar packed
  • 1 ½ teaspoons salt
  • 1 tablespoon pure vanilla extract
  • 2 large eggs at room temperature
  • 2 cups (240 g) all-purpose flour
  • 1 ½ cups (150 g) old fashioned oats

Filling:

  • 1 ½ cups (360 g) creamy peanut butter

Chocolate Frosting:

  • ¼ cup (57 g) unsalted butter softened
  • ¼ cup (60 ml) milk whole or 2%
  • ¼ cup (25 g) unsweetened cocoa powder
  • 3 cups (360 g) powdered sugar
  • 2 teaspoons (10 ml) pure vanilla extract

Instructions

  • Preheat the oven to 350°F (180°C), or 160°C fan oven. Grease a 9x13 inch (approx. 23×33 cm) baking pan.
  • In a large bowl, mix together melted butter, 1 cup peanut butter, granulated sugar, brown sugar, salt, vanilla, and eggs until well combined.
  • Gradually fold in the flour and oats until smooth.
  • Press the mixture evenly into the prepared pan.
  • Bake for 15-20 minutes or until lightly browned. Let it cool.
  • Melt 1.5 cups of peanut butter in the microwave in 20-second intervals, stirring after each, or using a double boiler on the stovetop.
  • Spread over the cooled base and refrigerate to set slightly.
  • In a medium saucepan, melt the ¼ cup butter over low heat. Add the milk and cocoa powder, whisking until smooth.
  • Remove from heat. Gradually stir in the powdered sugar, one cup at a time. Mix in the vanilla.
  • Spread the frosting over the set peanut butter layer.
  • Refrigerate the bars for at least an hour to set the frosting. Once set, cut into squares and serve.

Notes

  • Choose the right oats: Quick or instant oats don't have the right texture for this recipe. Be sure to use old-fashioned rolled oats for the best result.
  • Pay attention to the chilling steps: You want the base to be mostly cooled before adding the peanut butter, and you want the peanut butter to be set before adding the frosting. Before cutting into the bars, give them at least an hour in the fridge to set and cool fully.
  • Try some toppings! Cover the top of these peanut butter chocolate bars with chopped Reese's cups, chocolate chips, or sprinkles to make them extra tasty and festive.
  • Storage: Store in an airtight container in the fridge or at room temperature for up to 5 days. 

Nutrition

Serving: 1bar | Calories: 440kcal | Carbohydrates: 50g | Protein: 9g | Fat: 24g | Saturated Fat: 9g | Polyunsaturated Fat: 4g | Monounsaturated Fat: 10g | Trans Fat: 0.4g | Cholesterol: 41mg | Sodium: 272mg | Potassium: 221mg | Fiber: 2g | Sugar: 35g | Vitamin A: 321IU | Calcium: 35mg | Iron: 1mg