1) Whip the egg whites until they form hard peaks, set aside. Whip the egg yolks with the sugar until you reach a pale yellow color. Whip in the mascarpone cheese for 5 minutes.
2) Fold in the egg whites to the mascarpone cream and mix. Pour a layer of mascarpone cream into a large glass bowl or small individual bowls top with a layer of sponge fingers soaked in the espresso coffee. Repeat this operation 2 more times.
3) Finish with a mascarpone cream layer and sprinkle with the coffee powder.