Step 1

Peel and quarter 1 medium yellow onion. Cut 3 of the medium scallions crosswise into thirds. Peel and slice 1 (2-inch) piece ginger into thin rounds (about 1/4 cup). Quarter 1 of the medium lemons.

Step 2

Heat 1 tablespoon neutral oil and 1 teaspoon toasted sesame oil in a large heavy-bottomed pot over medium heat until shimmering. Add the ginger and cut scallions, spread into an even layer, and cook undisturbed until the scallions are starting to brown, 2 to 3 minutes. Meanwhile, pat 3 pounds bone-in, skin-on chicken thighs dry with paper towels.

Step 3

Add the chicken, onion, lemon, 7 cups water, and 2 teaspoons ground ginger to the pot. Increase the heat to high and bring to a boil. Reduce the heat to low, cover, and simmer until the chicken is cooked through and the meat is tender, about 35 minutes. Meanwhile, finely chop the remaining 2 medium scallions and thinly slice 1 medium jalapeños for garnish if desired.

Step 4

Using tongs, transfer the chicken to a medium bowl or clean cutting board. Use 2 forks to shred the meat into bite-size pieces. You can either discard the chicken skin, or chop it up and add to the meat. Return the bones to the pot and simmer uncovered for 10 minutes more.

Step 5

Meanwhile, season the chicken meat with 3 tablespoons yuzu kosho, 3/4 teaspoon kosher salt, and 1/2 teaspoon black pepper. Finely grate the zest of the remaining 1 medium lemon and 2 garlic cloves directly into the bowl. Juice the lemon into the bowl (about 3 tablespoons). Using tongs, toss everything to combine.

Step 6

Fit a colander or fine-mesh strainer over a large bowl. Pour the broth through the strainer. Discard the contents of the strainer, then pour the broth back into the pot. Add 1 tablespoon fish sauce and 1 tablespoon chicken bouillon powder and stir until the powder is dissolved. Add the chicken meat and stir to combine. Serve garnished with the scallions and jalapeño, with cooked rice or noodles if desired.