The bread barrier is the fix

Keeping a tuna or egg salad sandwich from going soggy comes down to building a barrier between the bread and the filling.

The wet stuff is the filling. If it touches bread directly, that’s it — you’ve got a sponge. So put something between them. A slice of cheese works, but the classic move is a thin smear of butter or mayo on both slices of bread. Fat repels water. It’s the same reason people butter the bread on a tomato sandwich.

Lettuce also works, but I’d use it in addition to butter, not instead of it. A dry leaf of romaine or a few spinach leaves gives you a solid layer that won’t just dissolve. If you’re feeling fancy, a light toast on the bread will buy you a couple extra hours, too.

And if you’re dealing with really loose, dripping filling, cut your losses: pack the filling in a separate container and assemble the sandwich at lunch. Less convenient, but zero sogginess.

A handful of lettuce isn’t just for crunch.