Start by whisking the egg yolks and ¾ cup sugar over a double boiler till pale and thickened. They should form a ribbon on the surface. If using a thermometer you want it to be 160 F. Set aside to cool.
Using a paddle attachment whip the room temp mascarpone and remaining ¼ cup sugar on low speed until smooth. Set aside.
Using the same bowl and paddle whip the cooled egg yolk mixture on medium speed. Add the mascarpone and mix on low. Set aside.
Using the whisk attachment whip the cream on medium low to get soft peaks. Add the mascarpone egg mixture and whip on low to incorporate.
Start by making your hot coffee. If using Nescafé use 2 tbsp for 2 cups boiling water. Dip each lady finger and line the bottom of a 9 inch pan. Pour ⅓ of the cream mixture. Repeat with a layer of cookies. Add another ⅓ of the mixture. Repeat with last layer of cookies. You can either pipe or smooth the remaining cream. Refrigerate 4-6 hours. Dust with cocoa powder and enjoy!
