Of all the flavor-packed proteins that can stretch the middle of a Vietnamese banh mi sandwich, my favorite probably isn't among the most popular of fillings. Barbecued pork, lemongrass chicken, spicy meatballs, and even tofu can all make for a deliciously filling banh mi. But for me, I usually opt for the sardine banh mi when I happen across a banh mi shop.
Sardine banh mis are usually made with canned sardines packed in a spicy tomato sauce. The rich, meaty flavor of sardines along with the spice and tang from the tomato sauce can lift a baguette in ways that other fillings can't. And since canned sardines are used, this particular type of Vietnamese sandwich is a cinch to make at home. No grilling or roasting of meats is necessary—just open the can of sardines and mash the fish into the sandwich, bones and all (they're edible, you know).
And when combined with the usual banh mi accoutrements of mayonnaise, pickled carrots and daikon, fresh cilantro, jalapenos, and a drizzle of Maggi seasoning, a simple tin of sardines transforms into a savory and satisfying sandwich.