1. Separate the egg whites from the yolks. Place the yolks, 1/4 cup sugar and salt in the bowl fitted with the whisk. Mix at speed 7 for 1 minute 30 seconds. Add the mascarpone and mix at speed 7 for 2 minutes. Transfer to a separate bowl and wash the Prep&Cook bowl and whisk very well.
2. Place egg whites in the bowl fitted with the whisk and launch at speed 7 for 2 minutes. Add 1/4 cup sugar and let work at speed 7 for 4 minutes, without the stopper. Using a spatula, gently fold the egg whites into the mascarpone mixture. Fold in whipped cream.
3. Dip the ladyfingers quickly in the coffee and arrange in a 10 x 10-inch dish. Spread cream over the top. Cover with plastic wrap and refrigerate for at least 1 hour. Sift cocoa powder over the cream just before serving.