The first time I had this I was with Wilma at a restaurant at the corner of Dalhousie and Clarence (I think). They put the mixture on a plate and put the lady fingers around it. It was very good (the lady fingers stayed crisp) and that is the way I served this for years. But now I prefer doing it the way I've outlined below.
2 packages of lady fingers
5 large egg yolks
5 Tbsp granulated sugar
500 gr Mascarpone (I could not find a 500 gr container so bought 2-275 gr and it worked out fine)
5 Tbsp Kahlua
5 egg whites
1 cup strong black coffee
1 cup unsweetened cocoa powder
Using an electric mixer, whisk egg yolks and the sugar until pale yellow, then fold the mascarpone into the yolks. Add the Kahlua
Whisk the egg whites to stiff but not dry peaks; stir 1/3 of the whites into the yolks and mascarpone mixture then gently fold in the rest.
With a pastry brush, brush coffee onto enough lady fingers to line the bottom of the serving bowl. Gently pour a layer about 1” thick of mascarpone mixture over the lady fingers; spread it evenly with a spatula. Place ¼ of the cocoa powder in a fine mesh sieve and sift over the mascarpone. This completes one layer. Repeat the process 2 or 3 times and finish with a layer of cocoa.
Cover with plastic and refrigerate overnight