Instructions

Prep: 

1. At least 30 minutes before baking, take the eggs (2 large) out of the refrigerator to come to room temperature. Measure out the rest of the ingredients.
2. Position an oven rack in the center position. Preheat the oven to 325°F/165°C. 
3. Line an 8-inch (20 cm) square pan with parchment paper leaving overhang on all sides. How to Perfectly Line a Square Pan with Parchment.

Make Infused Butter for the Buttercream:

1. Melt the butter (227 grams, 1 cup) in a saucepan over medium heat.
2. Roughen up the fresh mint leaves (14 grams, 0.5 ounce package) by rolling them around in your hand. You want to break them up a bit so that the flavor can easily escape. Add them to the saucepan and stir until the leaves are fully covered. Turn up the heat to medium-high for 1 minute.
3. Turn off the heat, cover the pot, and set it aside to steep. The longer it steeps the more flavor will extract. Steep for a minimum of 30 minutes.
4. After steeping, strain out the mint leaves. Cool the butter completely until it solidifies but still stays soft. You can speed this up by placing the butter in the fridge.
   

While the infused butter is solidifying, Make the Brownies: 

1. Melt the butter (113 grams, ½ cup) either in the microwave or in a saucepan on the stove. The butter needs to be very hot! 
2. In a large mixing bowl, whisk together the granulated sugar (100 grams, ½ cup), brown sugar (150 grams, ¾ cup), and cocoa powder (53 grams, ⅔ cup). Add the hot melted butter and whisk to combine. 
3. Add the vanilla extract (2 teaspoons) and the eggs (2 large), whisking vigorously for about 30 seconds. 
4. Add the salt (½ teaspoon), baking soda (⅛ teaspoon), and flour (85 grams, ½ cup + 3 tablespoons) to the bowl and stir with a mixing spoon or silicone spatula for about 30 seconds to help develop the gluten/chewiness. 
5. Transfer the brownie batter into your prepared pan and spread evenly.
6. Bake at 325°F/165°C for 28-33 minutes until a toothpick inserted in the center comes out with moist crumbs clinging to it. 
7. Set the pan on a cooling rack to cool completely.

While the brownies cool, make the buttercream:

1. In the bowl of a stand mixer fitted with a paddle attachment, or in a large bowl with a hand mixer, beat the softened infused butter on medium speed for about 1 minute, until fluffy. Scrape down the sides and bottom of the bowl.
2. Add the powdered sugar (300 grams, 2 ½ cups) into the mixing bowl and start mixing on low until the sugar starts to combine with the butter. Turn the mixing speed up to medium-high and beat for about 3 minutes until the mixture is light and fluffy. Mix in the salt (¼ teaspoon).
3. Add a bit of milk or heavy cream (28-42 grams, 2-3 tablespoons) if needed to thin out the texture. If the texture becomes too thin, you can add a bit more powdered sugar until you get a spreadable consistency. 
4. Add green food coloring one drop at a time until you get a soft mint color. I used one drop of gel food coloring.
5. Top the buttercream over the completely cooled brownies. Spread the buttercream evenly using a spatula. Move the pan to the fridge for at least 30 minutes.

Make the ganache:

1. Chop the chocolate (113 grams, 4 ounces) up into small pieces and place in a large mixing bowl. Alternatively you can use chocolate chips. 
2. Heat the cream (118 grams, ½ cup) in a saucepan over medium heat until it is simmering. 
3. Pour the hot cream over the chocolate and let stand for 5 minutes. Add the salt (one pinch).
4. Put the whisk directly in the center of the chocolate/cream mixture and begin whisking in small circles and slowly moving outward in bigger circles until the mixture is smooth. 
5. Let ganache cool to room temperature. It will thicken as it cools.
6. Once cooled, spread the ganache ovenly over the frosted brownies using a spatula. Return to the fridge for at least 30 minutes.
7. Using the parchment overhang, carefully remove the brownies from the pan. Cut into squares and serve.