Sopa de lima is a classic Mexican soup from the Yucatán Peninsula. Brothy, spicy and usually chicken-based, it counts as a key ingredient the juice of limas, or Mexican bittersweet limes, a variety of citrus that is difficult to find here in the U.S. To approximate the flavor of limas, we use a combination of freshly squeezed grapefruit juice and standard lime juice; credit for this substitution goes to J. Kenji López-Alt of Serious Eats. Adding the citrus juices at the very end, after cooking is complete, keeps the flavors clear and bright. The broth for sopa de lima is sometimes infused with warm spices for complex flavor and aroma. Maricel Presilla’s recipe from “Gran Cocina Latina” informed our version, which includes cinnamon, allspice and cumin, along with oregano. Simmering bone-in chicken thighs in store-bought chicken broth yields a deeply flavorful base for the soup along with an ample amount of tender meat to shred and add back to the pot. But before simmering, we brown the skin side of only half of the chicken thighs; this develops enough caramelization to build depth of flavor but spares the time and mess of browning both sides of all 3 pounds of thighs. Sopa de lima is garnished with strips of fried corn tortillas that, when lightly soaked with broth, take on an appealing chewy-crunchy quality that adds textural appeal to the soup. For simplicity, however, we use tortilla chips.