Ma's Prawns - Another Pantry

Ingredients

• 3 onions
• 150ml mustard oil
• 1 tsp ginger paste
• 1/2 tsp garlic paste
• 1/2 tsp ground turmeric
• 1 1/2 tsp chilli powder
• 1/2 tsp ground cumin
• 1/2 tsp ground coriander
• 2 green chillies, slit in half
• 1 tsp salt
• 1.25kg raw peeled prawns, deveined
• fresh coriander, to garnish