Preheat the oven to 302°F (150°C) and grease and line an 8 x 8-inch baking pan.
Melt the dark chocolate and butter in a double boiler until almost completely melted. Remove from the heat, add the instant espresso powder and stir until completely melted. Set aside to cool.
In a large bowl, beat the eggs and sugar until it turns light yellow. Add the vanilla extract and continue to mix.
Pour the chocolate mixture and stir until smooth. Add the flour and cocoa powder and mix thoroughly.
Pour the brownie batter into the prepared pan. Smooth the top with a spatula and bake for 45 to 50 minutes, or until a toothpick inserted comes out with some crumbs.
If adding After Eight chocolates to your brownies, lay them on top of the baked brownies 5 to 10 minutes after the brownies have come out of the oven.
Let the brownie cool completely before cutting.