You can substitute 2 cups freshly brewed espresso for the water and instant-espresso powder.
Tiramisu can be chilled up to 2 days.
Picture this: Your fork gliding through a cloud of featherlight zabaglione mixed with mascarpone and whipped cream, a bit of cocoa settling on the tines, and then through Italian ladyfingers softened by their dip in liqueur-spiked espresso. This tiramisu is a dream of a dessert—not least because it's so easy to put together.