Pupusas are everywhere in Washington, but nowhere does the concentration of cheese-filled tortillas seem greater than on a single stretch of University Boulevard in Maryland.

The east-west corridor, connecting Wheaton to College Park, may be best known as a traffic-clogged artery, but if you’re daring enough to cruise the strip, you can sample a wide range of the Salvadoran comfort food, from a shellfish pupusa packed with shrimp to a rice-flour variety that’s thin and crisp.

Why are pupusas so prevalent there? Much like Ethiopian cuisine’s injera, pupusas represent the D.C. region’s increasing diversity and the culinary gifts brought here through immigration. Following a civil war in El Salvador in the 1970s and two earthquakes in 2001, Salvadorans began arriving to Washington until, according to the U.S. Census, the metro area became home to more Salvadorans than any other city in the United States. Certain neighborhoods became known for their Salvadoran restaurants, including Mount Pleasant and Arlington. Over time, more restaurants began popping up in Maryland’s inner suburbs, thanks to the area’s lower rents and bigger spaces.

The dish traces its roots back centuries ago to the Pipil tribe in Central America. In El Salvador, as well as surrounding countries such as Guatemala and Honduras, it’s a popular breakfast staple, and the stores, stands and trucks that sell them are often under the domain of women, says Maritza Hernandez, who owns Pupuseria La Familiar, in Wheaton and in College Park, alongside her three sisters.

Hernandez’s pupusa recipe was passed down from her mother, who migrated to the United States in 1990 hoping to open a pupuseria after having owned a stall in the main plaza of Cojutepeque. Her mother died in a car accident in 2006, and operating La Familiar, Hernandez says, has been her chance to realize her mother’s vision.

Her cooking — and memory — lives on at Hernandez’s restaurants, where everything but the corn flour and cheese is made in-house. “We pride ourselves on making that same style and flavor of pupusas [my mother] made in El Salvador,” Hernandez says. “It’s our family’s recipe and tradition.”

Each pupuseria on University has its own recipe for the perfectly portable dish — a hot, stuffed pocket of quesillo cheese that oozes with molten grease and is usually made from either corn or rice flour. The most common varieties are revueltas (a mix of beans, pork and cheese), frijoles (beans), chicharrón (fried pork), ayote (squash) or loroco (edible buds from a flowering vine grown in Central America). But you can also find pupusas stuffed with jalapeño and even ham and cheese.

Whichever you choose, be sure to take advantage of the sides. Pile your plate high with curtido — a slaw of pickled cabbage, carrot and onion — for added crunch, acidity and heat. Add more fire with a side of tomato salsa, a thin, pureed sauce typically spiked with hot pepper. You can use your hands, or take a more civilized approach with a fork and knife, but really there’s no wrong way to eat a pupusa — whether it’s for breakfast, lunch, dinner or simply a midday snack.

Just don’t ask what’s in it. Although quesillo cheese is bountiful in El Salvador, it can be difficult to come by in Washington. So pupuserias usually develop their own mix. Hernandez uses a three-cheese blend, but she’s tight-lipped about the recipe. “Es como un secreto,” she says. Translation: It’s basically a secret.

Make these six pit stops along University Boulevard to sample the pupusa’s diverse range.

Delgado's Eatery

Located in the rear parking lot of the Wheaton Laundromat, this pupusa truck has a single card table and paper plates for alfresco dining. On most weekends, the parking lot is filled with cars and patrons coming and going with fresh-folded laundry — and foam containers packed tight with pupusas. Your options are simple, such as bean and cheese or cheese and pork pupusas. Order the latter, which is spiced with subtle heat. The truck also serves Mexican-style tacos, tortas, burritos and fajitas. Just be sure to bring a few dollars (it’s cash-only) and call ahead, because hours can vary. (It’s typically open 11 a.m. to 8 p.m. daily).

11323 Georgia Ave., Wheaton. 240-277-5007. $2.

Pupuseria La Familiar

At Pupuseria La Familiar, you can watch soccer and telenovelas in front of steaming, fresh pupusas. As the name implies, this spot is meant to feel intimate. Maritza Hernandez wants you to feel as if you’re a guest in her home. You might find her in the kitchen making pupusas by hand or in the dining room mingling with regulars. Aside from generous portions and hearty fare, the staff and service add to the down-home vibe: Hernandez’s relatives, including her son, Hector, work right alongside her.

11324 Fern St., Wheaton. 240-669-4280. pupuserialafamiliar.com. $1.85.

Samantha's Restaurant

For sit-down, white tablecloth service, head to Samantha’s, which serves a tasty shellfish pupusa made with shrimp and scallops. Diners be warned: The parking here is limited, and it’s first-come-first serve for a table, meaning you might have to wait, especially during peak periods on Saturdays and Sundays. Most patrons don’t seem to mind. Maybe it’s because the chips and salsa are unlimited, or that the restaurant puts tender, loving care into its curtido, which is made extra-crunchy with thick-cut vegetables and a welcome kick of spice.

631 University Blvd. East, Silver Spring. 301-445-7300. $2.25.

Pupuseria El Comalito

An oversize strip mall with a Starbucks and Chuck E. Cheese’s is where you’ll find one of the busiest and best pupuserias in Takoma Park. On most weekends, the dining room at El Comalito rocks with Latin music as waitstaff carry trays two at a time, filled with pupusas and such drinks as horchata and melon with pineapple. The service is brisk, but the pupusa-making process takes time. An army of cooks delicately forms each pupusa by hand, then it’s off to the grill station with the corn cakes, where rows of the rounds are cooked to golden-brown, before being flipped, seared again and plated. The menu is one of the most extensive in the area: There are 18 varieties of pupusas, all under $2 each, including spinach and cheese, squash and cheese, pork and loroco, and chicken and cheese.

1167 University Blvd. East, Takoma Park. 301-445-2225. $1.79.

Pupuseria La Cabanita

For a side-by-side look at how pupusas can vary, head to Pupuseria La Cabanita, where you can sample rice and corn pupusas in one sitting. Out of all the pupuserias on University Boulevard, this spot excels at cooking the perfect rice-flour pupusa, a variety commonly found south of San Salvador that’s a thinner and crisper version than the corn-flour style. To satisfy your sweet tooth, try the traditional Guatemalan drink atol de elote, a silky-sweet blend of corn, milk, sugar, cinnamon and vanilla served warm in a foam cup.

1511 University Blvd. East, Hyattsville. 301-408-1119. $2.

Pupuseria Irene's

Throughout the years, Irene Cuevas’s namesake restaurant has expanded across Prince George’s and Montgomery counties. But this location is the original — and the smallest of the bunch, with seating for only about 20. It’s a no-frills dining experience, but you should consider buying your pupusas in bulk, because the demand is high. Waitresses move quickly, shuttling plates of piping-hot pupusas that burst with cheese. For a timeless take, try the chicharrón con queso, which, in this writer’s opinion, still tastes like it did more than two decades ago. And at just under $2, the price point hasn’t changed much, either.

2218 University Blvd East, Hyattsville. 301-431-1550. $1.75.