William-Sonoma Tiramisu

6 egg yolks
3/4 c sgar
1 ob marscapone cheese, softened
2c heavy cream, chilled
2T rum
1t vanilla
3c espresso
5 egg whites
40-50 lady fingers
cocoa powder

-beat egg yolks and sugar until pale yellow and thick (4-5 minutes) OVER A PAN OF SIMMERING WATER, BUT NOT TOUCHING WATER
-add marscapone cheese until smooth in CHILLED mixing bowl
-add rum, vanilla adn 2T espresso, beat until smooth
-clean bowl: beat whites to stiff peaks
-fold in marscapone mix with spatula until smooth
-add 1c of beaten egg whites
-add remaining whites
-submerge lady fingers in espresso and place on bottom of 6qt glass dish
-spread half marscapone mix over ladyfingers
-arrange another layer of ladyfingers, spread remaining marscapone mix
-dust with cocoa powder
-chill 4 hours to 1 day before serving