To make the crust: Pulse the cookies in a food processor until finely chopped. Add the butter and mix until the cookie crumbs are evenly moistened. Press the mixture across the bottom and 1" up the sides of a lightly greased 9" or 10" springform pan. Refrigerate to set the crust., To make the filling: Whisk the egg yolks with 1/4 cup (49g) of the sugar in a medium mixing bowl over 1" of simmering water, until the mixture is light-colored and thick, able to hold a ribbon as it drops off the whisk back into the bowl. This will take 3 to 4 minutes; be sure to whisk continuously. Remove from the heat., In a separate bowl, beat the cream cheese with the remaining 1/4 cup (49g) sugar until fluffy and completely smooth. Whisk into the warm egg mixture; then add the Irish whiskey cream liqueur and mix until evenly combined., In a small heatproof dish, combine the gelatin and water; let sit for 3 minutes. Heat gently over hot water or at low power in the microwave in 10-second bursts, swirling until dissolved. Whisk the dissolved gelatin into the cream cheese mixture., Whip the heavy cream to soft peaks and fold it in. Pour the filling mixture on top of the crust in the pan and use a small offset spatula to smooth the top. Chill, uncovered, for at least 1 1/2 hours, until set., To unmold the cake: Run a thin spatula around the edge of the pan to free the cake before unclipping the pan and removing the side. Cool the cake completely., To make the topping: Heat the cream and chocolate together over low heat, stirring until the mixture is smooth. Pour into a pool in the center of the cake, as shown; or drizzle over the top and down the sides., Storage information: Store any leftovers, well wrapped, in the refrigerator for several days.