Dip each biscuit into the espresso; place in a single layer on bottom and around sides of a glass or ceramic baking dish, about 8 inches square or similar capacity. Combine the water and powdered egg whites in a large stainless-steel bowl, stirring gently until the powder dissolves, 3 to 4 minutes. With an electric mixer, beat at medium-high speed until stiff peaks form, 5 to 7 minutes.
In another large bowl, beat together the ricotta, egg substitute, mascarpone and sugar. Stir in about one-third of the beaten egg whites, then gently fold in the remainder with a rubber spatula. Pour over the ladyfingers. Cover and refrigerate 6 to 8 hours. Sprinkle with the cocoa just before serving.
Description: "Tiramisu is a festive way to end a holiday meal."