Bring a medium sauce pot of generously salted water to a boil. Break the bucatini into bite-size pieces, then add to the boiling water and cook until just tender, 10 to 12 minutes. Drain and set aside.
While the bucatini cooks, prepare the vegetables and start the soup.

• Trim the root ends from the leek; cut the leek in half lengthwise, then crosswise into thin half-moons. Soak the half-moons in a medium bowl of cold water, allowing any dirt to settle at the bottom. Skim the leek from the surface of the water and pat dry.
• Grate or peel and finely chop enough ginger to measure 1 teaspoon [2 tsp].
• Strip the parsley leaves from the stems; coarsely chop the leaves for garnish.

Prep and cook instructions are identical for both chicken options.

• Pat the chicken dry with a paper towel; season generously with salt and pepper.

In a large sauce pot over medium-high heat, warm 1 tablespoon [2 TBL] oil until hot but not smoking. Add the leek and mirepoix, season with salt and pepper, and cook, stirring occasionally, until the vegetables start to soften, 2 to 3 minutes. Stir in the ginger and garlic-herb blend and cook until fragrant, about 1 minute. Add the chicken broth and 2 cups [4 cups] water and bring to a boil. Add the chicken, making sure the pieces are separated, and return to a boil. Reduce to a simmer, cover, and cook until the chicken is cooked through, 6 to 8 minutes. Using a slotted spoon or tongs, transfer the chicken to a plate to cool slightly; let the soup continue to simmer. Using a fork, shred the chicken into 1-inch pieces. Return the chicken to the soup, stir in the bucatini, and continue cooking until heated through, 1 to 2 minutes. Season to taste with salt and pepper.

Transfer the soup to individual bowls, garnish with the parsley, and serve.