Preheat the oven to 350°F (175°C). Line a 9x9-inch baking dish with parchment paper.
In a microwave-safe bowl, melt the butter. Place the chocolate chips in a mixing bowl and pour the melted butter over them. Let sit for a couple of minutes and then whisk together until melted.
Add the granulated sugar, brown sugar, eggs, and vanilla extract. Mix until well combined.
Add the flour and salt. Mix just until combined.
Pour the batter into the prepared baking dish and spread evenly.
Bake for 35-40 minutes, or until a toothpick inserted in the center comes out with only a few moist crumbs. Let cool completely before frosting.
In a mixing bowl, beat the softened butter until creamy.
Gradually add the powdered sugar, milk, peppermint extract, and green food coloring. Mix until smooth and fluffy.
Spread the mint frosting evenly over the cooled brownies.
Place chocolate chips in a bowl and set aside.
In a small saucepan or microwave-safe bowl, warm the heavy cream until it just turns hot (not boiling).
Pour the warm cream over the chocolate chips and let sit for a minute, then stir until smooth.
Spread the ganache over the mint frosting and smooth it out evenly.
Chill the brownies in the fridge for at least 15 minutes before slicing.
Keyword brownie recipe, brownies, chocolate, layered brownie, mint