Crackling Tiramisu Cake

I remade the original tiramisu recipe in a cracked style. The tiramisu cream is made with mascarpone cheese, fresh cream, egg yolk, sugar, and water. The coffee syrup uses instant coffee powder, hot water, sugar, and karua. The chocolate coating is made with chocolate and cocoa powder. If you want to reduce the sweetness, remove the sugar from the coffee syrup or reduce the amount of sugar in the tiramisu cream. Be careful because if you reduce the amount of sugar, the yolk will cook quickly when boiling. At this time, raise the temperature of the yolk to below 149℉ and stir vigorously.