Mix the eggs, sugar and 1 tablespoon of the Marsala in a bowl and place over a small saucepan of barely simmering water, ensuring the bowl doesn’t touch the water. Whisk, preferably with a hand-held blender, until the mixture is foaming and warm. Remove from the heat and continue whisking until slightly cooled. Combine the mascarpone and crème fraîche in a large bowl and slowly fold in the egg mixture. Combine the coffee, remaining Marsala, chocolate essence (if using), and icing sugar in a shallow bowl. Dip the biscuits, 2 pieces at a time, into the coffee mixture, holding for about 5 seconds, then place in serving glasses. Top with a few spoonfuls of mascarpone mixture. Repeat until you have 2 or 3 layers of savoiardi and mascarpone mixture in each glass. Refrigerate for six hours at least, then shave or grate chocolate on top and serve. SIMON SAYS: Chocolate essence is available from food markets like Farro Fresh. I have used Nielsen Massey Pure Chocolate Extract. Chilling is definitely necessary, and it certainly won’t hurt if you make it the day before and leave it overnight.