Sweet and Sour Prawns

Ingredients

• 12 l large prawns, shelled, deveined, heads and tails intact
• 150 ml millilitres water
• 4 spring onions, thinly sliced
• 3 cm ginger, peeled and sliced thinly
• 1 tsp teaspoon salt
• 1 tbsp tablespoon tomato paste
• 4 tbsp tablespoons white vinegar
• 4 tbsp tablespoons white sugar
• 1 tsp teaspoons olive oil
• ½ tsp teaspoon salt
• 1 tbsp tablespoon olive oil
• 3 tsp teaspoons white sugar
• 1 tsp teaspoon sea salt