Use three flavor power players.
At Bunk Sandwiches in Portland, Oregon, Tommy Habetz lets customers add bacon, pickled chilies, or marinated anchovies to any sandwich. Add all three and he actually offers a discount – that's how much he believes in piling on flavor. "You get all those elements of smoky, salty, sweet, spicy – they do everything you want flavor to do," Habetz says. If you're not feeling that bold, any one of the three will do – and they're not hard to doctor up. Habetz recommends buying decent pickled chilies or anchovies, draining them, and remarinating them in good olive oil with a little crushed garlic and sprigs of thyme.