Clean and prepare the thawed shrimp by removing the shells, except for the tail, and making an approximately 1-1½ centimeter deep cut along the back to remove the black vein.

Rinse the lemongrass, pound them with a rolling pin on the cutting board, and then cut them in half.

Peel the onion and cut it into narrow wedges.

Clean the mushrooms of any soil and cut them into quarters.

Rinse the tomato and cut it into narrow wedges.

Cut the chilies diagonally into thin strips.

Pour the water into a pot and bring it to a boil.

Add lemongrass, ginger, lime leaves, fish sauce, tamarind juice, chili, chili paste, tomato, and lime juice to the boiling water.

Cover the pot and let the soup boil for a while to allow all the flavors to develop.

Then add the onion and mushrooms.

Let the soup continue to boil for a few more minutes.

Now add the shrimp and let them boil with the soup for a maximum of 2-3 minutes or until the shrimp just turn reddish. If the tiger shrimp boil for too long, they become very dull and rubbery to chew.

Taste and optionally adjust with more chili paste, fish sauce, and lime juice.

The taste should be on the sour and especially SPICY side ;-)

Serve the steaming hot soup immediately and optionally sprinkle a bit of fresh, chopped Thai basil and/or cilantro on top.