Recipe - Mint Brownies

Brownie Layer:

1/2 cup (113 grams) unsalted butter, cut into pieces
4 ounces (114 grams) dark chocolate, coarsely chopped
1 1/4 cups (250 grams) granulated white sugar
1 teaspoon pure vanilla extract
2 large eggs
1/2 cup (70 grams) all purpose flour
1/4 teaspoon salt

Mint Layer:

2 tablespoons (28 grams) unsalted butter, at room temperature
1 cup (115 grams) confectioners (powdered or icing) sugar, sifted
1 tablespoon nonfat Greek yogurt (this was heavy cream in the original recipe)
1/2 teaspoon pure peppermint extract or 1-2 tablespoons crème de menthe
green food coloring (optional) (I used a mix of blue and yellow powdered food coloring)

Chocolate Glaze:

3 ounces (90 grams) semisweet chocolate, chopped (Here, I used Scharffen Berger 70%)
1 tablespoon (14 grams) unsalted butter.

Preheat oven to 325 degrees F (160 degrees C) and place the rack in the center of the oven. Have ready a 9 x 9 inch (23 x 23 cm) square baking pan that has been lined with parchment paper across the bottom and up two opposite sides of the pan, like a sling. (You can also use buttered aluminum foil for this, but I like parchment because for me, it tears less and is easier to work with.) Set aside.

Brownies: In a stainless steel (heatproof) bowl placed over a saucepan of simmering water, melt the butter and chocolate. Remove from heat and stir in the sugar and vanilla extract. Add the eggs, one at a time, beating well (with a wooden spoon) after each addition. Stir in the flour and salt and beat, with a wooden spoon, until the batter is smooth and glossy and comes away from the sides of the pan (about one minute). Pour the brownie batter evenly into the prepared pan.

Bake in the preheated oven for about 25 minutes or until the brownies start to pull away from the sides of the pan and the edges of the brownies are just beginning to brown. A toothpick inserted in the center of the brownies will come out almost clean. Remove from oven and place on a wire rack to completely cool.

Mint Layer: In the bowl of your electric mixer, or with a hand mixer, beat all the ingredients until smooth. Add a few drops of green food coloring if you want the frosting green. If the frosting is too thick, add a little extra cream. (The frosting should be just thin enough to spread.) Spread the frosting evenly over the cooled brownie layer. Place in the refrigerator for about 5-10 minutes or until firm.

Chocolate Glaze: In a heatproof bowl over a saucepan of simmering water, melt the chocolate and butter. Spread over the mint filling and refrigerate for about 30 minutes or until the chocolate glaze starts to dull.

Found here