Combine the crushed ladyfingers with melted butter and espresso. You can crush them using a food processor or put them in a Ziploc bag and roll over with a rolling pin until coarsely crushed. Press the mixture into an 9-inch springform.
In a small bowl, pour boiling water over gelatin. Stir until gelatin is completely dissolved. Let cool slightly. If it cools too much and it hardens, microwave for 15-20 seconds. Do not boil. This step is optional. I have never had luck getting the filling firm enough without the gelatin.
Combine the cream cheese, sugar, and coffee in the bowl of a stand mixer fitted with a paddle attachment (alternatively, use a hand mixer and a large bowl). Mix at low speed to form a thick paste, and then increase to medium speed until soft and smooth. Scrape the bowl and beater with a flexible spatula, then switch to the whisk attachment and pour in the cream. Whip at high speed until stiff peaks form.
Gradually beat in gelatin mixture into the cream cheese mixture, if using. Scrape into prepared crust and spread into an even layer. Transfer the cake to the freezer until set, for about an hour.
In a medium-size bowl, whip the cream with the mixer on high speed until it thickens and soft peaks begin to form. With the mixer still running, add the sugar and beat until the stiff peaks form. Beat in vanilla. Gently fold in the mascarpone with a rubber spatula.
Top the cold cheesecake, still in the pan, with a layer of ladyfingers briefly dipped into coffee. Break a few into pieces to fill in the empty spaces.
Spoon the mascarpone mixture on top of the ladyfingers and gently even out with a frosting spatula without disturbing the layer. Return to the freezer for 15-30 minutes or until set.
Meanwhile, place the chocolate into a medium bowl. Heat the cream in a small saucepan over medium heat. Bring just to a boil, watching very carefully because if it boils for a few seconds, it will boil out of the pot.
When the cream has come to a boil, pour it over the chopped chocolate and let sit until chocolate has softened, about 3-5 minutes.
Add butter and whisk until smooth. Allow ganache to cool slightly before pouring over a cake.
Remove the cake from the freezer. Release and gently remove the sides of the springform (you can let it stand at room temperature for 10 minutes before removing the sides).
Pour chocolate ganache over the tiramisu cheesecake. Start at the center of the cake and work outward.
Decorate the cake as desired.
See post for layer suggestions.
Carefully slide a pie server under the crust, making sure it reaches all the way to the tip of the wedge (the first slice is the most difficult and messy to remove).
Nutrition information is approximate and meant as a guideline only.