Speedy Nectarine Jam

Using the point of a knife, score each nectarine. Place in a bowl then cover with boiling water and leave until the skins start to pull away from the fruit. Peel the fruit, remove the stones from the nectarines and chop flesh into small pieces. Weight of the fruit should be 1kg.

Place the fruit and Chelsea Jam Setting Sugar into a large heavy based 6 litre saucepan. Heat fruit and sugar over low heat, stirring occasionally until the sugar dissolves. Add the butter and bring to a rapid boil.

Boil for 4 minutes, carefully skimming off any foam that forms on the surface during cooking.

Test for set: Spoon a small amount of jam onto a cold plate. Allow to cool slightly, then draw your finger through the jam. If the surface wrinkles, then remove from the heat. If the surface doesn't wrinkle, return to the heat and boil for a further 2 minutes and test for set again.

Pour into sterilised jars and seal.

To sterilise jars: Preheat oven to 100°C. Wash jars in warm soapy water, rinse and dry thoroughly. Place the empty jars and lids on a tray in the oven while you make the jam. They should be hot when you pour in the jam.