FILLING: Combine egg yolks and sweetener in the top of a double boiler, over boiling water. Reduce heat to low, and cook for about 10 minutes, stirring constantly. Remove from heat and whip yolks until thick and lemon colored. Add mascarpone to whipped yolks. Beat until combined. In a separate bowl, whip cream to stiff peaks. Gently fold into yolk mixture and set aside.

Cut the crust off the psmf bread lady fingers and cut into 2 inch “fingers” and line the bottom and sides of a large glass bowl. Brush with coffee. Spoon half of the cream filling over the lady fingers. Repeat ladyfingers, coffee and filling layers. Garnish with cocoa. Refrigerate several hours or overnight.