The classic tuna salad sandwich features a mix of textures and flavors with tuna, mayo, onions, and celery. Adding fish sauce to the mix can enhance your sandwich’s umami flavor.

Fish sauce is made by fermenting small fish like anchovies or shrimp and then salting the mixture. Its umami flavor is similar to Worcestershire or soy sauce, but more mellow.

You only need to add a little fish sauce to make a difference in a tuna sandwich. Mixing ½ teaspoon into the mayo, lemon juice, or other dressings can be enough.