Most bánh mì sandwiches in the District have no guts. I mean that literally. A truly authentic Vietnamese sandwich includes one important ingredient: liver. Many Americanized outlets, including Bonmi and ShopHouse Southeast Asian Kitchen, skip the gizzard entirely. Not Sundevich, the barely year-old joint hidden in an alley off of 9th Street NW in Shaw. The chicken liver mousse, made fresh next door by Seasonal Pantry’s master offal craftsmen, Dan O’Brien, is the undisputed star in a cast of strong characters that includes pork terrine, pickled carrots and daikon, cucumber and fresh herbs. The full production is rich, funky, spicy and sweet. “Bastardizing the sandwiches is the opposite of everything we believe in,” says Sundevich owner Ali Bagheri. “We want them to be true to the tradition, and you either get it or your don’t.” We get it. And we get it often.