At Brothers and Sisters in Washington, D.C., pastry director Pichet Ong’s riff on a proper British trifle retains the classic form while reinventing the components. Cheesecake stands in for egg custard; pound cake replaces ladyfingers. Rather than sherry, Ong’s trifle uses saba, a syrup made from cooking down grape must, which has a flavor similar to balsamic vinegar. Look for it from San Giacomo on amazon.com, or substitute pomegranate molasses. For a summer update on this trifle, swap strawberries for sour cherries; use grapes in the fall.