Shoyu Cabbage Soup

vegetable oil

medium onion, thinly sliced

carrots, peeled, thinly sliced

celery stalks, thinly sliced

garlic cloves, chopped

head Napa cabbage, chopped

low-sodium vegetable broth

(or more) shoyu (Japanese soy sauce)

unseasoned rice vinegar

sugar

cooked ramen or soba noodles

Hot chili paste (such as sambal oelek) and fresh cilantro leaves (for serving)

Shoyu and hot chili paste can be found at Asian markets and in the Asian foods section of many supermarkets.