Wash the plums and remove any leaves and stalks. Pierce the plums all over with a fork or the tip of a sharp knife, then halve (leave the stones in). Tip into a large, sterilised, sealable jar (about 2 litres) with a wide neck – the plums should easily fit inside. Alternatively, divide between two smaller jars.

Sprinkle over 150g sugar and add the gin (reserve the gin bottle if you’re planning to decant the plum gin back into it later). Seal the lid and give the jar a good shake. Store in a cool, dark place for at least a month, giving it a shake every few days for the first week or so to mix everything together and dissolve the sugar.

Check the flavour after a month and continue to infuse if you prefer a stronger flavour – it can be left for up to three months. Or, add another 50g sugar and leave for two or three weeks if you prefer it sweeter. When you’re happy with the flavour, strain the gin through a fine mesh cloth or muslin into a clean bottle and discard the fruit (you can also eat the boozy plums alongside sponge cakes or ice cream). Store in a cool, dark place. Drink on its own, in a G&T or mix with lemon juice and sugar syrup for a plum gin sour.