Grape, apple & vanilla jam

Sterilise 3 x 300g jars (find sterilising instructions at waitrose.com/howtosterilisejars). Put the grapes in a bowl. Cut the apples into 0.5cm cubes (or pulse in a food processor until finely chopped) and add to the bowl with ½ of the lemon juice; stir well.

In a large pan, mix 450ml water, the sugar and remaining lemon juice. Bring to the boil over a high heat, stir to dissolve the sugar, then simmer for 5 minutes. Add the fruit and its juices, plus the lemon zest, cinnamon, vanilla pod and seeds. Bring to the boil, then reduce the heat and simmer gently for 1 hour, stirring occasionally. Towards the end, mash the fruit with a potato masher until it is a uniform colour with a jammy consistency. Test for setting*. Discard the vanilla pod, pour into the jars and seal. It will keep for 4 months. Once opened, keep in the fridge for up to 4 weeks.