In a large stockpot, heat 3 tablespoons of oil to medium-high heat. Add crushed garlic and chopped onions, and stir until onions just start to brown. Add the can of crushed tomatoes, cumin, cayenne pepper, chili powder, salt, pepper, and half of the lime juice. Turn up the heat until it bubbles, stirring constantly, then gradually stir in chicken stock. Turn down to low and simmer for 10 minutes. Add diced chicken. (Optionally add black beans or fresh corn kernels).
To make the tortilla crisps, julienne 12 corn tortillas into narrow, uniform strips. In a saucepan, bring 1 cup of vegetable oil up to medium-high heat (takes about 5 minutes to come up to temperature -- be sure to test the heat of the oil by placing a corn tortilla bit into the oil -- it should bubble immediately). Deep-fry these tortilla strips in batches (2 mins or so -- do not let them turn a dark brown) -- transfer to paper towel to dry. They should be crispy.
When ready to serve, plate the soup, then top with a mound of the tortilla strips.
Squeeze fresh lime juice into each bowl at the table.
Soup itself can be made ahead, but make the corn tortilla strips fresh, just prior to serving... it's worth it.
How much stock fits safely in a standard stockpot when multiplying a recipe for twelve servings? Doubling batches requires tracking pot volume closely; standard eight-quart vessels will overflow if ingredients scale beyond a certain threshold. Liquids expand during rapid boiling phases, so maintain at least two inches of headspace below the rim. Thermal mass increases alongside volume, meaning large quantities take significantly longer to reach a simmer once cold chicken stock enters the pot.
Adjusting Batch Sizes Safely
Proportions shift non-linearly when expanding aromatics like onions and garlic. Double the garlic carefully, because sulfur compounds concentrate intensely during extended simmering periods. Reduce added cayenne and chili powder by ten percent initially when scaling upward, then adjust heat levels at the final tasting stage. Spices do not multiply at an exact one-to-one ratio without overpowering subtle tomato acidity.
Frying Mechanism and Substitutions
Starch gelatinization dictates how corn tortillas crisp in hot oil. Water content inside the tortilla flashes to steam instantly at 350 degrees Fahrenheit, creating rigid internal air pockets. Store-bought baked chips provide a fat-reduced alternative, though they lack the porous surface area required to absorb broth without immediate structural collapse. Freshly fried strips maintain structural integrity longer under hot liquids.