Using an stand mixer with whisk attachment, beat egg yolks and sugar until thick, about 5 minutes. Add room temperature mascarpone to the egg yolks and beat until smooth. Add 1 tablespoon of espresso and one tablespoon of balsamic and mix until thoroughly combined.
In a shallow bowl, mix the remaining espresso and Dark Chocolate Balsamic. Briefly dip each ladyfinger into espresso mixture. Allowing the ladyfingers soak too long will cause them to fall apart. Place the ladyfingers on the bottom of a 13 by 9 inch baking dish, breaking them in half if necessary in order to fit the bottom.
Evenly spread 1/2 of the mascarpone mixture over the ladyfingers. Arrange another layer of soaked ladyfingers and top with remaining mascarpone mixture. Cover with plastic wrap and refrigerate for at least 2 hours or up to six. Before serving, sprinkle the top with chocolate shavings.