Pastel de tres leches is a sponge cake -- one that's soaking up three, yes three, kinds of milk. It's very rich and sweet, with a dense, wet consistency similar to bread pudding. Most of the time, the three milks are condensed milk, evaporated milk, and fresh milk or cream. But you can get creative in the kitchen and try everything from melted ice cream to eggnog in place of the milks.
Several countries, including Mexico, Cuba, Panama, Puerto Rico and Costa Rica, claim to be home to pastel de tres leches. It's found a place for itself in the United States, too, where some regions sell ice cream flavors based on its sweet, mild taste.