3 Tbsp salt
2 1/2kg pickling onions peeled
500g Chelsea White Sugar
2 Tbsp Chelsea Golden Syrup
1 Tbsp allspice
1 Tbsp ground cloves
1 tsp dried mustard powder
1 Tbsp curry powder
3 litres malt vinegar
2 1/2 Tbsp cornflour

Sprinkle salt over the pickling onions and cover with cold water. Stand for 24 hours. Strain and then pack tightly into jars. Put all remaining ingredients except cornflour into a heavy-bottomed saucepan and bring to the boil. Boil for 2 minutes. Mix cornflour to a paste with cold water, then stir into the mixture. Reduce heat and stir until thickened. Pour into jars, covering onions completely. Leave for at least 3 weeks before eating.