Step 1

Make the broth: In a 4- to 5-quart pot over high heat, combine the water, chicken, garlic, ginger, scallion whites, salt and pepper, if using, and bring to a boil. Reduce the heat to medium-low and simmer, uncovered, stirring occasionally, until the chicken is tender and cooked through, about 15 minutes.

Step 2

Make the sauce: While the chicken simmers, in a small bowl, whisk together the vinegar, soy sauce, sesame oil and chili crisp, to taste, if using.

Step 3

Make the soup: Using a slotted spoon or tongs, transfer the chicken to a cutting board. Add the noodles (see Notes) and carrots to the broth and cook following the directions on the noodle package, about 3 minutes.

Step 4

While the noodles cook, using two forks, shred the chicken into bite-size pieces. Return the chicken to the pot and rewarm for 2 minutes. Taste, and season with more salt and/or pepper, as needed, keeping in mind that the finishing sauce will add both saltiness and heat.

Step 5

Divide the soup among bowls. Add the scallion greens, and drizzle each bowl with 1 teaspoon of the soy sauce mixture, placing extra sauce and chili crisp on the table, if desired.