Seven-layer taco dip generally includes refried beans, sour cream, guacamole, salsa or chopped tomatoes, shredded cheddar cheese, sliced black olives and green onions. Some recipes omit guacamole or include ground beef or lettuce. Recipes also vary in the exact layering order of each topping.
While recipes for 7-layer taco dip differ considerably, nearly all recipes start with a bottom layer of mashed refried beans, typically seasoned with a prepared taco seasoning mix. Most recipes that use guacamole call for it to be layered next, on top of the beans, followed by a layer of sour cream. For those not using guacamole, the sour cream goes on top of the beans. Some recipes call for mixing the sour cream with cream cheese or green chillies for more flavor. The next layer is typically cheddar cheese, followed by a layer of salsa, such as pico de gallo or simply chopped tomatoes. Finally, the dip finishes with a layer each of chopped black olives and chopped green onions.
Some recipes calling for ground beef have it mixed with the refried beans, while others keep the beans and ground beef separated with a layer of cheddar cheese. In these cases other toppings, such as the black onions or green onions might be omitted to keep it to seven layers. Sometimes recipes that call for shredded lettuce don't include guacamole.
Although the origin is unknown, 7-layer dip is inspired by Tex-Mex cuisine and is believed to have become popular in the 1970s or 1980s. It is typically served with tortilla chips.