Preheat the oven to 180°C. Line a springform pan (24 cm in diameter) with parchment paper.Whisk the eggs with the sugar until creamy and pale in colour. Combine the flour and the coffee instant powder and stir in the egg mixture. Spoon the batter into the springform pan. Bake for 15 minutes. Cool slightly, remove from the cake tin and cool completely.

Soak the gelatin. Bring the coffee to a boil and add the sugar and the coffee cream. Take from heat and stir until the sugar has dissolved. Squeeze the gelatin and dissolve in the still warm coffee mixture. Place in the fridge.

Beat the single cream until stiff. Add in the coffee liqueur, if desired. Fold half of the single cream in the gelatinising coffee cream. Place a cake ring around the cake and divide evenly the coffee cream on top. Cool for 1 hour.

Remove the cake ring and garnish the cake with the remaining whipped cream and chocolate shavings.