1. Separate lobster’s head and body, using only the head, chop into pieces.
2. Sauté ginger slices with a little oil, stir in lobster heads, add around a dozen white peppercorn, sauté well. Pour boiling water and let the ingredients cook for a while to extract more flavour, then tip the lobster heads and water into a stock pot, cook 45 mins in medium heat.
3. Use a knife to score a “X” on the bottom of the tomatoes, blanch for 3-4 minutes, then soak in iced water at once, peel off the skin, cook the skin in the lobster soup; quarter the tomatoes.
4. After boiling the soup for 45 mins, pour it through a strainer and return the soup into the pot, add peeled potato wedges and cook for another 30 mins, then add tomato quarters and boil 10 mins more. Season with a little fish sauce and sugar, serve.