3 ounces unsweetened chocolate, chopped
1 1/2 cup sugar
3 large eggs
2 teaspoons instant espresso powder
1 teaspoon pure vanilla extract
1/4 teaspoon salt
3/4 cup flour
1/4 cup Walnuts (optional)
2 ounces semi sweet chocolate chopped or chocolate chunks (optional)
Buttercream:
5 large egg whites
1 1/4 cups sugar
1 1/2 cups unsalted butter, cut into cubes, room temperature
1/2 tablespoon pure vanilla extract
2 teaspoons espresso powder
2 teaspoons boiling water
Pinch of salt
To make the brownies, preheat the oven to 325 degrees Fahrenheit. Butter and line a 8 × 8-inch baking tin with parchment paper, leaving a 1-inch overhang on the two longer sides. Melt the chocolate and butter in a heatproof bowl set over a saucepan of simmering water at low heat until the chocolate is melted. Remove from heat and whisk in sugar. Add the eggs, one at a time, stirring until smooth after each addition. Whisk in the espresso powder, vanilla, and salt. Sift flour over the chocolate mixture and stir gently to blend well. Add the walnuts and chopped chocolate. Pour the batter into the prepared baking tin. Bake brownies until puffed and dry looking and until a cake tester inserted in the center comes out with a few moist crumbs attached, about 30 to 35 minutes. Remove from oven and transfer to a wire rack. Cool completely in the tin. Using the paper overhang, carefully lift the brownies out of the pan. Cut in squares. While the brownies are baking, make the buttercream. In a small bowl, mix the espresso powder with the boiling water. Reserve. Make sure there is no grease in the bowl and on the utensils you’ll be using for the buttercream. Add egg whites and sugar to a heatproof bowl (or bowl of standmixer) set over a saucepan of simmering water at low heat, whisking constantly until temperature reaches 160 degrees Fahrenheit. Whisk with a stand mixer until the meringue is thick and glossy and the bowl doesn’t feel warm to the touch. With mixer on low speed, add the butter a cube at a time. Mix until it has a silky texture. If it looks curdles, continue beating until smooth. You can’t overbeat the buttercream. Add vanilla, salt and espresso, beat until combined. Pipe or spoon a small amount of buttercream on top of each brownie square. Add shredded chocolate and a coffee bean if desired.