01 -
Turn your oven on to 350°F. Butter a 9x13 inch metal pan and lay parchment paper inside so nothing sticks.
02 -
Melt butter in a small saucepot at a low temperature. Take off the heat, stir in the chocolate chunks until smooth (heat for 10 seconds more if needed), and let it cool for a bit.
03 -
Combine cocoa powder, espresso powder, and flour in a small mixing bowl. Sift them together and set aside.
04 -
In a separate large bowl, whisk up the eggs, sugars, salt, and vanilla extract. Beat using a mixer on medium-high until the batter is pale and thick. When the mix drips off, it should slowly disappear from the surface.
05 -
Carefully fold the melted chocolate mixture into the whipped egg mix. Then, slowly fold in the dry ingredients, careful not to knock out too much air.
06 -
Pour the batter into your prepared pan, smooth out the top, and bake for about 25 minutes. The surface should crack a little and feel soft to the touch. Let the pan cool on a rack before moving on.
07 -
Whisk together mascarpone and heavy cream in a bowl for about 30 seconds until mixed. Add in espresso powder, sugar, salt, and vanilla bean paste, then beat for another 1-2 minutes on medium-high till soft peaks hold up.
08 -
Use a spatula to spread your espresso cream over the fully cooled brownie base. Lightly dust the surface with cocoa powder using a sieve, cut into squares, and enjoy now or refrigerate.