Tamarind prawns with lime rice

Ingredients

• 1 bunch spring onions
• 4 tbsp vegetable oil
• 50g ginger, finely chopped
• 2 red chillies, seeds removed, shredded
• 750g raw prawns, shelled
• 2 tsp tamarind concentrate
• 1 tsp toasted ground cumin
• ½ tsp garam masala
• 50g jaggery or 2-3 tbsp dark muscovado sugar
• 2 tbsp coriander, chopped
• 3 tbsp raw peanuts, skinned
• 3 tsp mustard seeds
• ½ tsp turmeric
• Rind of 1 large lime, grated
• Juice of 1-2 limes
• 250g basmati rice, boiled and cooled