Sweetbreads are the thymus glands of young lambs and calves. They are highly perishable and should be soaked and cooked on the day of purchase. Once prepared as shown, they can be coated in egg and breadcrumbs and fried; in classic French cuisine, they are served with sauce poulette.

1. Soak for 2 hours in several changes of cold water. Rinse, put in a pan and cover with cold water. Bring to the boil and blanch 3 minutes.

2. Drain and refresh under cold running water, then remove outer skin and any pieces of membrane.

3. Place sweetbreads between two plates, put a weight on top and chill for 2 hours until firm.

4. Slice the sweetbreads at an angle using a sharp knife. The sweetbreads are now ready for cooking.