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A thin mint brownie sitting on a plate

Thin Mint Brownies

Makes 1 9x13 baking dish
Course Dessert
Author Melissa Au



  • 1 9 x13 triple chocolate brownie mix
  • eggs
  • oil
  • water
  • 1 9 x13 baking dish fitted with parchment paper

Mint Frosting

  • 1 C unsalted sweet cream butter softened
  • 3 tbsp heavy whipping cream
  • 2 1/2 C powder sugar
  • 2 tsp mint extract
  • 2 -3 drops of kelly green food coloring
  • 1 piping bag fitted with a star tip

Chocolate ganache

  • 1/2 C unsalted sweet cream butter melted
  • 1 11 oz bag of milk chocolate chips
  • 1/2 Package of Keebler grasshopper cookies



  • preheat oven to 350 degrees
  • Using a standing mixer, prepare the brownie mix according to the box
  • Bake in the oven for 20 minutes
  • While the brownies are baking, prepare the frosting
  • Using the standing mixer, combine all ingredients and mix on medium speed until combined and smooth
  • Scoop frosting into the piping bag
  • Once the brownies are baked, let cool to room temperature
  • Once the brownies are cooled, pipe the frosting around the brownies
  • Using a flat spatula or knife, smooth the frosting out over the brownies
  • Set aside while you make the chocolate ganache
  • Using a small sauce pan, heat up the heavy whipping cream until it start to simmers
  • Pour the chocolate chips into a medium bowl
  • Pour the heavy whipping cream over the chocolate chips and let sit for a few minutes
  • Using a whisk, mix until smooth
  • Pour ganache over the frosting
  • Using a ziplock bag and a rolling pin, crush up the grasshopper cookies into crumbles
  • Sprinkle the crushed cookies over the ganache
  • Place into the fridge for an hour or until ganache hardens
  • Cut into bars and enjoy!