Szechuan Carrot Soup

Time: about 1 hourMakes 6 servings Ingredients 1 medium onion1 celery stalk, chopped1 garlic clove, minced1 teaspoon vegetable oil1 pound carrots cut into 1 inch pieces3/4 inch piece of fresh ginger, pealed and sliced thin1/8 teaspoon dried hot red pepper flakes3 cups chicken broth1 1/2 tablespoons soy sauce1 1/2 tablespoons creamy peanut butter1 teaspoon sugar1