Place a saucepan over a medium low heat and add the sugar and 6 egg yolks. Whisk until thoroughly mixed.
6 large eggs, 1.5 oz sugar
Add the milk and raise the heat to medium. Cook over a medium heat stirring constantly until it reaches a gentle boil.
2/3 cup full milk
Allow to continue boiling for about 1 minute and then remove from the heat. Place to one side to cool off.
When easy to handle, transfer to a bowl, cover with a lid or clingfilm and place in the fridge to chill.
Add the cream and vanilla to mixing bowl and whisk together, either by hand or far easier with an electric mixer. You need to have stiff cream forming.
1 ¼ cup double cream, ½ tsp vanilla extract
Recover the egg and milk mixture from the fridge and add the mascarpone cheese. Whisk until lovely a smooth.
1 lb mascarpone
In a separate bowl, add the strong coffee and rum and stir well.
¼ cup espresso coffee, 1 tbsp rum
Now you need to be sorted and in order. Have the sponge fingers ready, next to the coffee/rum mixture which should be next to the serving dish. I use a glass 11x7 inch dish so you can see the layers.
Cut the sponge fingers lengthways in half and dunk into the coffee/rum mixture. Before they become soggy, transfer them to the serving dish forming a layer.
6 oz sponge fingers
Then add half of the mascarpone mixture over the sponge fingers spreading it evenly and gently.
Then add half of the whisked cream mixture on top and again spread evenly and gently.
Repeat the process of building layers using the remaining sponge fingers, coffee/rum, mascarpone and cream mixtures.
Using a fine sieve, sprinkle the cocoa powder over the top.
Cocoa powder
Carefully cover and refrigerate for at least 5 hours. This helps everything blend perfectly.
Serve with a sprig of mint on top for that finishing touch.