Preheat the oven to 350°F. Butter an 8-inch springform cake pan.
Put the chocolate, butter, and sugar into a heatproof bowl set over a pan of simmering water (the bowl shouldn’t touch the water). Melt the mixture, stirring a little. Remove the bowl and let it cool for about four minutes. Stir in the egg yolks, one at a time.
Beat the egg whites with an electric hand-mixer until they form medium peaks (stiff but with the peaks drooping slightly). Using a big metal spoon, fold the ground almonds into the chocolate mixture along with half the egg whites, then fold in the rest of the whites.
Scrape the batter into the prepared pan and bake for 35 minutes. Cool completely, carefully unlatch the sides of the pan, and remove the base. Transfer the cake to a serving plate. It will deflate and crack as it cools. Whip the cream until just holding its shape, then drizzle in the coffee and whiskey, still whipping. Add the confectioners’ sugar and taste for sweetness and booziness. Dust the cake with confectioners’ sugar and serve with the cream.