The bulgogi (Korean ribe-eye steak) bánh mì at Del Seoul
 

The Vietnamese version of a sub sandwich is defined by the French-style baguette encasing it—bánh mì, after all, translates loosely to “bread”—and is often crowned with cucumber spears, pickled carrots and daikon, cilantro, jalapeños, and mayo. But what comes between the slices runs the gamut from traditional (pork roll) to fusion (Korean bulgogi). Here, a guide to the Southeast Asian sensation poised to give the Italian beef a run for its money in Chicago.

Top traditional combo

Bun Mi Cha Lua (pork roll), $4.85 at BUN MI EXPRESS (3409 N. Broadway; 773-661-2228)
The fillings: Salty, bologna-like sliced pork roll, made from minced pork that’s been steamed in a banana leaf, mixes with the rich nuttiness of pâté with a burnt-orange hue.
The bread: The ten-inch baguette isn’t exactly house-made (the dough comes from a bakery in Quebec), but it holds up without turning soggy.
Bonus: The jovial owner, Lee Trinh, graciously doles out samples from his menu, such as super-moist orange bread and syrupy Vietnamese iced coffee.

Tastiest bread 

Hen House, $7 at SAIGON SISTERS (567 W. Lake St., 312-496-0090; French Market, 131 N. Clinton St., 312-496-0094)
The fillings: Sweet caramelized chunks of dark meat chicken meld with a zesty marinade of lemongrass and ginger. A squirt of lime and a sprinkling of crumbled peanuts top it off.
The bread: A flawless combo of chewy and crusty that stays intact even when saturated with juices, this one rules the roost.
Bonus: Saigon Sisters’ two Loop-adjacent locations satisfy the downtown work crowd’s bánh mì cravings. But convenience comes at a price: $7 to $8 per sandwich (almost double the cost of most others).

Choice vegetarian

Tofu Xào Gù’ng (ginger tofu), $3.50 at NHU LAN BAKERY (2612 W. Lawrence Ave.; 773-878-9898)
The fillings: Scene-stealing tofu could impress even staunch carnivores. The robust slices pick up the ginger’s spiciness, but cucumber spears subdue the bite.
The bread: Thick and spongy, the baguette threatens to stand in the way of the prize inside. Less would be more.
Bonus: At $3.50, it’s easy on the pocketbook, leaving enough spare change for a cup of sweet chè thu’ng (a soupy concoction of coconut and red beans) from the refrigerated case.

Best fusion

Bulgogi (Korean rib-eye steak), $5.95 at DEL SEOUL (2568 N. Clark St.; 773-248-4227)
The fillings: The beef looks like gyro meat and tastes kind of like beef jerky with a hint of sweet soy; a slather of red pepper aïoli subs for mayo.
The bread: Fresh, flaky, and deeply scored, it’s worthy of its stuffing.
Bonus: Although not every combination jells as successfully as the addictive bulgogi (breaded sesame-chili shrimp were brittle and oversauced), Del Seoul spices up its bánh mì with a Korean slant.

Honorable mention

Friendliest shop: BA LE (5014 N. Broadway; 773-561-4424)
The fillings: The sandwich that an employee dubbed “the most delicious thing ever” (veggie avocado, $3.95) overflows with fresh avocado and jicama, but Subwayesque additions of Swiss cheese, tomato, and black olives are pedestrian.
The bread: These extra-crusty, golden-hued beauties are baked on-site in an open kitchen. They’re also sold in bulk at the shop’s extensive grocery.
Bonus: With patient staffers and a bevy of chè, pastries, salads, and boxed snacks to try, this is the ideal launching pad for the Viet-novice.