Separate the egg yolk from the egg white and beat with the sugar to a frothy cream. Add the mascarpone and mix with the whipped egg whites. Dip the ladyfingers in the coffee and cover the bottom of a flat dish. Cover with half of the mascarpone cream and smooth out. Dip the remaining ladyfingers in coffee and spread over the mixture. Finish with the cream. Dust the dessert with cocoa powder at the end. Put something into the fridge. And serve cold. I always leave the tiramisu in the refrigerator for 2-3 hours. But every refrigerator is different. Therefore, please check the cooling time yourself. Have fun copying.