Flamed Shrimps With Rouille and Herb and Lemon Rice

• 1.5 kg (3 lbs) raw shell-on prawns or shrimps
• 1 litre stock

Remove the shells and heads from the prawns and make a litre (1¾ pints) of stock by boiling the debris in a litre or so of water. Strain it into a clean saucepan, and stir in the rice. Bring to the boil, cover and lower the heat to the meres