True Thai Tom Yum Soup - Fiery Prawn Broth - Yummy Gusto

Ingredients

• 300g unpeeled prawns/shrimp with their heads on
• 3 cups water
• 1/2 cup mild chicken stock
• 2 lemongrass stems, outer part removed
• 1.5cm chunk of galangal, cut into 4 slices
• 5 kaffir lime leaves, roughly ripped
• 2 small hot chillies
• 3 cloves of garlic
• 120g oyster mushrooms
• 1 roma tomato, sliced into wedges
• 1/2 medium white onion, chopped into 1cm chunks
• 1 tsp sugar
• 3 tbsp fish sauce
• 3 tbsp fresh lime juice
• Handful of fresh cilantro for topping
• 1 1/2 tbsp Nam Prik Pa (Thai spicy roasted sauce)
• 1/3 cup evaporated milk