1. Place chicken stock in a large pot over medium high heat. Add the lime leaves, minced lemongrass (and lemongrass stalks, if using fresh lemongrass). Bring to a boil.

2. When soup reaches a bubbling boil, turn heat down to medium. Add the garlic, red chili (or cayenne pepper), mushrooms, lime juice, and fish sauce. Stir well. Partially cover with a lid and allow to gently boil for 3 minutes.

3. While soup is simmering, remove shells from shrimp. (The tail can be left on, if desired).

4. Add the shrimp, gently stirring them into the soup. Also add other vegetables, if using. the shrimp (and vegetables will cook almost instantly - in 1 minute or so. (Try not to over-cook the shrimp, or you will lose that wonderfully tender texture.

5. As soon as the shrimp are cooked (they will turn uniformly pink and be nice and plump), remove soup from heat.

6. Do a taste test, looking for a balance of salty, sour, and spicy. If the soup needs more salt, add 1 Tbsp. more Fish Sauce. If it's too sour, add 1-2 Tsp. Sugar. If too spicy (Tom Yum is meant to be spicy!) add a little Coconut Milk. If too salty add another squeeze of lime juice. (The saltiness of your soup will depend on how salty your stock was to start with).

7. As a final touch, add a dollop or two of Thai Nam Prik Pao chili sauce. The chili sauce/paste will turn the soup a little red in color, and will bring the flavor up to a whole new level. It can also be served on the side in small dishes so each person can add as much or as little as they prefer.

8. Ladle the soup into bowls and top with a generous sprinkling of fresh Coriander/Cilantro and Basil.