Thukpa | Tibetan Chicken Noodle Soup

Name: Thukpa | Tibetan Chicken Noodle Soup
Ingredients: 200 g boneless chicken (I used chicken breast); 1 tablespoon oil; ½ cup chopped onion; 1 tablespoon chopped ginger; 1 tablespoon chopped garlic; ½ cup chopped coriander (cilantro stem); ¼ cup chopped tomatoes; 1 green chili (chopped); 1 teaspoon ground cumin; 1 teaspoon ground coriander; 1 teaspoon ground black pepper; 2 cups chicken broth (stock); Juice of 1 lemon; 1 cup sliced vegetables, (carrots, cabbage, bell peppers or capsicum); 1 tablespoon light soy sauce; Salt to taste; 300 g cooked noodles, (preferably udon); Chili paste (homemade or store bought, to serve (see notes)); Chopped coriander (cilantro leaves, to garnish); Chopped spring onions (scallions, to garnish)