Pasta Shells with Prawns

• sunflower or olive oil
• 225 g (8 oz) cooked prawns in their shells

Heat 2 teaspoons sunflower or olive oil in a small, heavy-based saucepan. Remove the prawns from their shells and put the shells and heads in the hot oil. Turn the shells round in the oil until they stop sizzling loudly, then pour over the glass of wine. Let it evaporate for a moment, then add the glass of water. Cover and simmer for at least 30 minutes to extract maximum flavour from the shell