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No Bake Monster Cookie Bars

Chewy no-bake cookie bars loaded with oats, peanut butter, chocolate and M&M's for an easy crowd-pleasing treat.
Prep Time25 minutes
Total Time1 hour 25 minutes
Servings: 16 bars

Ingredients

  • 1/2 cup unsalted butter 1 stick, softened
  • 1/2 cup granulated white sugar
  • 1/4 cup light brown sugar
  • 1 cup creamy peanut butter
  • 1/2 cup all-purpose flour
  • 1 teaspoon vanilla extract
  • 2 cups rolled oats
  • 3/4 cup M&M's stirred into base
  • 8 ounces dark chocolate chips
  • 3 tablespoons heavy whipping cream
  • 1/4 cup M&M's for topping

Instructions

  • Line a 9-inch square pan with parchment paper, leaving an overhang on two sides for easy removal; set aside.
  • Soften the butter in the microwave 10–15 seconds if needed. In a medium bowl, beat the softened butter with the granulated and light brown sugars until combined.
  • Mix in the creamy peanut butter, scraping the bowl sides as needed, then add the all-purpose flour and vanilla and mix until the flour is incorporated.
  • Fold in the rolled oats, adding them gradually if desired, then stir in 3/4 cup M&M's until evenly distributed.
  • Press the cookie mixture firmly and evenly into the prepared pan to form a compact base.
  • Place the dark chocolate chips and heavy whipping cream in a microwave-safe bowl. Microwave in 30-second intervals, stirring between each, until the chocolate is melted and smooth.
  • Pour the warm chocolate ganache over the cookie base and spread into an even layer, then sprinkle the remaining 1/4 cup M&M's on top.
  • Let the ganache set at room temperature briefly, then refrigerate the pan until the bars firm up, at least 1 hour.
  • Use the parchment overhang to lift the bars from the pan and cut into 16 bars before serving.

Equipment

  • 9-inch Square Baking Pan
  • Parchment Paper
  • medium mixing bowl
  • Electric Mixer
  • Microwave-safe Bowl
  • Spatula
  • Measuring cups and spoons

Notes

  • Use a 9-inch pan for the listed yield.
  • Press the base firmly to ensure bars hold together.
  • Let ganache cool slightly before pouring to avoid melting the M&M's.
  • Refrigerate at least 1 hour to fully set.