The "Xis" is a popular sandwich that originated in the southern Brazilian state of Rio Grande do Sul. The name "Xis" is derived from how the letter 'X' is pronounced in Portuguese, which sounds like “cheese,” a fundamental component of the sandwich. The Xis sandwich is somewhat similar to a hamburger but differs in its size and preparation.

The Xis typically features a large, flat, and round bun, filled with a wide array of ingredients that can be customized according to personal preferences. Common fillings include ground beef or chicken, lettuce, tomatoes, corn, peas, cheese, and sometimes a fried egg or bacon. Condiments often used are mayonnaise, ketchup, and mustard. A distinctive feature of the Xis is its generous size, often requiring a fork and knife to eat.

The dish became popular in the late 20th century and is a staple in snack bars, street food stalls, and casual eateries across Rio Grande do Sul. The Xis is especially popular in cities like Porto Alegre, Santa Maria, and Caxias do Sul.

Cultural adaptations and variations of the Xis can be found, with different regions adding their own twist to the sandwich. The "Xis Coração," for instance, includes chicken hearts, a common variation in some areas. Vegetarian versions are also available, typically substituting meat with grilled vegetables or plant-based patties.

The Xis's popularity has gradually spread beyond Rio Grande do Sul, finding niche markets in other parts of Brazil. However, it remains most closely associated with Gaucho cuisine and culture. Its large size and adaptability in terms of fillings make it a versatile and satisfying meal option.