Put two saucers in the freezer for testing the jam later on. Tip the cherries, sugar and lemon juice into a large, heavy-based saucepan and simmer uncovered over a medium-high heat for 35-50 mins, stirring frequently until thick and glossy.

After 35 mins, spoon a little of the jam onto one of the chilled saucers. Leave for 1 min, press a fingertip into the jam. If it starts the wrinkle, it’s ready. If it slides away, continue to boil the jam for 10 mins, then test again on the other saucer.

Spoon the jam into sterilised jars and seal. Will keep for six months unopened (when stored in a dark, cool place), or opened in the fridge for three months.