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St. Patrick's Day Mint Oreo Brownies

Easy St. Patrick's Day Mint Oreo Brownies

These Easy St. Patrick's Day Mint Oreo Brownies feature a dense, fudgy chocolate brownie base loaded with crushed Mint Oreos, topped with a vibrant green mint buttercream and finished with a glossy chocolate ganache. Festive, rich, and perfect for parties, they’re ready in under an hour and taste even better the next day.
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Prep Time 25 minutes
Cook Time 25 minutes
Total Time 50 minutes
Servings: 16 squares
Course: Dessert
Cuisine: American
Calories: 380
Ingredients Equipment Method Notes

Ingredients
  

  • 1/2 cup unsalted butter
  • 4 oz dark chocolate (70%), chopped
  • 3/4 cup granulated sugar
  • 1/4 cup light brown sugar
  • 2 large eggs
  • 1 large egg yolk
  • 1 tsp vanilla extract
  • 1/2 cup all-purpose flour
  • 1/4 cup unsweetened cocoa powder
  • 1/2 tsp salt
  • 1/4 tsp espresso powder (optional)
  • 16 cookies Mint Oreo cookies, crushed (divided)
  • 1/2 cup unsalted butter, softened
  • 2 cups powdered sugar
  • 2-3 tbsp heavy cream (for buttercream)
  • 1/2-3/4 tsp peppermint extract
  • 4 oz dark chocolate (for ganache)
  • 1/2 cup heavy cream (for ganache)
  • 1 tbsp unsalted butter (for ganache)

Equipment

  • 8×8 inch baking pan
  • medium saucepan
  • mixing bowls
  • electric mixer
  • rubber spatula

Method
 

  1. Preheat oven to 350°F (175°C). Line an 8x8-inch pan with parchment and lightly grease.
  2. Brown the butter over medium heat until golden and nutty. Pour into a mixing bowl.
  3. Add chopped dark chocolate to hot butter and stir until smooth. Let cool slightly.
  4. Whisk in sugars, then add eggs, yolk, and vanilla. Whisk until glossy and thickened.
  5. Fold in flour, cocoa powder, salt, and espresso powder until just combined.
  6. Fold in most of the crushed Mint Oreos, reserving some for topping.
  7. Spread batter evenly in pan and bake 22–26 minutes until a toothpick shows moist crumbs. Cool completely.
  8. Beat softened butter until fluffy. Add powdered sugar, peppermint extract, cream, and salt. Beat until smooth and tint green with gel coloring.
  9. Spread buttercream evenly over cooled brownies and chill 20 minutes.
  10. Heat cream until simmering and pour over chopped chocolate. Stir until smooth, then add butter. Cool slightly.
  11. Pour cooled ganache over buttercream and top with reserved crushed Oreos. Chill at least 1 hour.
  12. Lift from pan and slice into 16 squares with a clean, warm knife.

Notes

Do not overbake the brownies—remove when a toothpick shows moist fudgy crumbs. Cool completely before adding buttercream. Let ganache cool to warm (not hot) before pouring. Chill at least 1 hour before slicing for clean layers.