Ginger Chicken Soup With Vegetables

Name: Ginger Chicken Soup With Vegetables
Ingredients: 2 tablespoons olive oil; 1 small red onion, thinly sliced; 3 cloves garlic, finely chopped; 3 tablespoons ginger grated fresh ginger; 2 32-ounce containers low-sodium chicken broth; 2 medium parsnips, peeled and chopped; 2 medium carrots, peeled and chopped; 2 stalks celery, thinly sliced; 1 medium turnip, peeled and chopped (1½ cups); ½ teaspoon kosher salt; 1 2- to 2½-pound rotisserie chicken; ½ cup frozen peas; 4 scallions, sliced; 4 biscuits, store-bought or made from a mix (optional)