This comforting soup, based on Mexican sopa de pollo con fideos, consists of toasted noodles in a tomatoey broth, enhanced by tender chicken and quick-charred garlic, jalapeño and onion. In place of fideos—the short, skinny wheat-based pasta traditionally used in the dish—we substitute easier-to-find capellini or vermicelli, broken into bite-sized pieces. The noodles are lightly browned, contributing toasty flavor and depth to the broth. Blistering the aromatics under the broiler adds smoky flavor, amplified as the mixture is reduced with fire-roasted tomatoes to form the soup’s base. We top each bowl with onion and cilantro for freshness and crunch, but sliced avocado or a dollop of sour cream would be delicious, too.