01 -
Butter and line an 8x4-inch metal loaf pan with parchment paper for easy removal.
02 -
Microwave chocolate chips and butter in 30-second bursts, stirring until smooth and glossy.
03 -
Stir in cocoa powder, sugar, and instant espresso powder into the melted mixture until sugar begins to dissolve.
04 -
Incorporate one whole egg and one yolk, whisking vigorously for 1 to 2 minutes to create a smooth, fudgy batter.
05 -
Sprinkle flour and salt over the batter and fold gently just until no dry patches remain; avoid overmixing.
06 -
Pour batter into prepared pan, smooth the surface, and bake at 350°F (175°C) for 25-30 minutes until edges pull away and the center slightly jiggles; internal temperature should reach 180°F (82°C).
07 -
Prepare a strong shot of espresso and allow it to cool completely before use; add coffee liqueur if desired.
08 -
Combine cooled espresso with coffee liqueur if using, for dipping the ladyfingers.
09 -
Whip mascarpone, sugar, and vanilla bean paste gently then add cold heavy cream and whip on medium speed until soft peaks form; refrigerate until needed.
10 -
Once brownies are cool, quickly dip ladyfingers into coffee soak and arrange them evenly over the top.
11 -
Pipe or spoon mascarpone cream over the dipped ladyfingers to cover completely.
12 -
Refrigerate the layered dessert for at least one hour to set. Before serving, dust generously with Dutch-process cocoa powder and slice with a sharp knife.