Frito Pie at Hill Country. (Goran Kosanovic/For The Washington Post)

You probably first encountered it at a high school football game: the iconic yellow and red bag of Fritos torn open, filled with chili — inevitably ladled out of a slow cooker — and topped with cheese and diced onion. Frito Pie, or Fritos Chili Pie, as it’s officially known by the Frito-Lay company, is a dish as simple as they come. In her 2011 book “Fritos Pie: Stories, Recipes, and More” (Texas A&M University Press), Kaleta Doolin, daughter of Fritos founder Charles Elmer Doolin, details the history of the company and the many curious recipes (Fritos Fruitcake! Fritos-Covered Ice Cream with Fritos Macaroons!) it has printed over the years.

The pie’s origins, like the dish itself, are a little messy: “I’m not sure whether Mother Doolin or Mary Livingston, Dad’s executive secretary, invented the recipe,” writes Doolin. “Maybe neither did and the recipe was invented by Nell Morris when the Frito Company acquired the Champion Chili Company in 1952.”

Doolin elaborates that the company credits the recipe to Morris, director of consumer services during the 1950s, although Doolin thinks the recipe was around before Morris was hired. Doolin also refutes the New Mexico claim to the dish — Teresa Hernandez began serving it at the Santa Fe Woolworth’s lunch counter in the 1960s — by citing the menu of the Dallas Dietetic Association’s 1949 closing banquet. In any case, modern-day iterations of the dish show that how it’s served is open to interpretation.

1. Corn chips

They provide crunch, salt and a hit of nostalgia. Hill Country and Meats & Foods keep it traditional, using Fritos brand chips. At Lyman’s Tavern, co-owner Kevin Perone prefers the shape and larger surface area of BonTon corn chips (made by Bickel’s Snack Foods, a subsidiary of Hanover Foods Corp.).

2. Chili

Hill Country’s beef chili is chunky and studded with pieces of pork sausage. Meats & Foods uses its rich, smooth beef or vegetarian chili. Lyman’s tops its pie with a basic ground beef chili embellished with black beans. In all cases, the slightly greasy chili matched with the corny, salty crunch of chips proves addictive.

3. Cheese

How do you make a good thing better? Add cheese — in this case, shredded cheddar. You’ll see more experimenting at Lyman’s, where in addition to cheddar, you’ll get a topping of Salvadoran crema.

4. Garnishes

To counteract all the rich, hearty flavors, a little sharpness in the form of an allium is necessary. Hill Country and Lyman’s top the pies with diced red onion, while Meats & Foods goes for the milder green onion. In another appreciated twist, Lyman’s adds house-pickled jalapeños.

Find Frito Pie in the District at Hill Country, 410 Seventh St. NW (202-556-2050); Lyman’s Tavern, 3720 14th St. NW (202-723-0502); and Meats & Foods, 247 Florida Ave. NW (202-505-1384).