From leftovers to a classic
Sopa de tortilla, sometimes called sopa azteca, is a soup of crisp tortilla strips served in a tomato and chile broth. The central idea is thrift. Tortillas are best fresh, and leftover ones dry out within a day or so. Rather than throw them away, cooks fry or bake them into crisp pieces and use them in soup, in the same spirit as chilaquiles and tostadas and totopos.
The precise origin of the dish is not documented in a way that lets anyone name a place or a year. It is commonly associated with central Mexico, and it appears in many home and restaurant repertoires today. The name “azteca” is more of a label than a historical claim, so it is wise to be skeptical of stories that tie the dish to a particular moment of the past.
The broth
The broth is the base of the soup and typically has the following elements:
- ripe tomatoes, roasted or boiled, then blended
- onion and garlic, either roasted or raw
- a chile, often a dried one such as pasilla or guajillo, sometimes with fresh chile
- chicken stock or water
The usual method is to blend the tomatoes, onion and garlic into a smooth puree. This puree is then fried in a little oil in the pot until it darkens and thickens, a step that deepens the flavor. After that, the stock goes in and the soup simmers for a while, long enough to marry the flavors. A sprig of epazote herb is a common addition in some kitchens, and others use fresh cilantro or a few leaves of mint.
Salt is added to taste, and the broth is strained if a very smooth texture is wanted. It should be thin enough to drink from a spoon and flavorful enough to stand on its own.
The tortilla strips
Corn tortillas that are a day or two old are cut into thin strips or small squares. They can be shallow-fried in hot oil until golden and crisp, then drained on paper, or baked in a hot oven on a tray until dry and crisp. Baking uses less oil and is easier to do safely; frying gives a richer flavor. When frying, use a deep enough pan, keep water away from the oil, and never leave hot oil unattended. Season the strips lightly with salt.
Some cooks add the strips to the broth in the pot, where they soften and almost melt into it. Others place them in the bowl and pour broth over just before serving to keep some crunch. Both are valid, and which is preferred is mostly a matter of taste.
The kind of tortilla matters a little. Thicker, handmade corn tortillas hold their shape better than very thin factory ones. Good corn tortillas are the foundation of the dish, since their texture decides how the strips behave in the broth.
Garnishes
The garnishes are as important as the broth and give the soup its identity. Typical options include:
- diced Hass avocado
- crumbled or cubed queso fresco, or a melting cheese in some versions
- a drizzle of crema
- thin rings of fried pasilla chile
- chopped cilantro and a squeeze of lime
- fried or crisp strips of tortilla piled high
The cool, creamy toppings contrast with the hot, tangy broth. These finishing toppings, such as crema and cheese, do for this soup what they do for many dishes: round out the sharp edges.
Variations
Some versions use a chicken stock, others use a vegetable broth. Some include shredded chicken, and some include beans or hominy, which makes the soup closer to a meal. Regional versions might include squash blossoms or fresh corn. Because the dish is not governed by one fixed recipe, the best test is whether the broth is lively, the tortillas are crisp or tender as desired, and the toppings are fresh.
Serving and storage
The soup is traditionally an opening course in a full midday meal, followed by rice or pasta and then a main dish. It is also a satisfying lunch on its own. For best results, store broth and tortilla strips separately: the broth refrigerates well and reheats until steaming hot, while the strips stay crisp in an airtight container at room temperature for a day or so. Assemble the bowls just before serving.