Singapore chilli crab

Ingredients

• 1/4 cup vegetable oil
• 1 large mud crab, cleaned
• 1/4 tsp salt
• 1 cup tomato passata
• 1 cup stock or water
• 2 tbsp palm sugar
• 1 tbsp white vinegar
• 1 tbsp soy sauce
• 3 spring onions, cut into 5cm lengths
• 1 tsp cornflour mixed with 2 tbsp cold water
• 1 egg, beaten
• 1/2 cup loosely packed coriander, to serve
• 1 bird's eye chilli, to serve