01 -
In a large mixing bowl, add the mascarpone cheese. Use an electric hand mixer to beat the mascarpone just until loosened and creamy. Add the whipping cream, powdered sugar, and vanilla extract. Beat until the mixture thickens, about 5-10 minutes. If you tilt the bowl, the mixture should just barely move and slide around the bowl. Set aside.
02 -
In a shallow bowl or tall cup, stir together espresso powder, hot water, and coffee liqueur.
03 -
Dip each ladyfinger into the espresso soak very briefly, only about 1 second on each side, and let the excess drip off. They should not be completely soaked through otherwise they'll become mushy and fall apart. Arrange the soaked ladyfingers in rows on top of the brownie layer.
04 -
Add the mascarpone cream on top of the ladyfinger layer. Use an offset spatula to smooth the cream into an even layer.
05 -
Chill the tiramisu brownies in the fridge for about 1 hour before slicing to allow the cream to set and ladyfingers to soften.
06 -
Right before slicing, use a fine mesh sieve to dust the top of the tiramisu with cocoa powder. Lift the entire sheet of tiramisu brownies out of the pan by pulling up on the parchment paper overhangs. Slice into squares with a large knife, wiping the knife in between each cut for clean-looking slices.