The Mexican crumbly aged cheese often used on tacos and elotes is cotija cheese.
Cotija is a firm, salty cow’s-milk cheese named after Cotija, a town in Michoacán. Its strong flavor and grainy texture make it especially useful as a finishing cheese: cooks crumble or grate it over tacos, elotes, tostadas, beans, soups, salads, and other dishes.
Cotija is not identical at every age. Younger versions can be softer and resemble feta, while aged cotija becomes drier, firmer, saltier, and more reminiscent of Parmesan. It softens when heated but generally does not melt into a smooth sauce, which helps it remain recognizable as a topping.
The cheese is commonly confused with queso fresco because both are white Mexican cheeses. Queso fresco is usually fresher, milder, and softer; cotija is typically more intensely salty and aged. Feta can substitute for fresh cotija, while Parmesan, Romano, or ricotta salata are closer substitutes for aged varieties. Traditional mountain cotija production is seasonal and associated with Michoacán’s rainy-season grazing.