Source:
https://scmp.com/article/991443/bachelors-jam

Bachelor's jam

Recently, while poking around the dusty shelf that I reserve for home-made preserves, I came across a forgotten jar of bachelor's jam, which, according to my notes, I had 'put up' two years ago. I tasted it and found that, over time, the berries, brandy and sugar had mellowed into a rich, fruity mixture that was still extremely potent. I'll be serving this as a digestif after a heavy meal or spooning the mixture over home-made vanilla ice cream.

Bachelor's jam reportedly got its name because it's easy enough for a bachelor to make (although most of my single male friends know their way around a kitchen). If you make a batch now, it should be ready to eat by next winter - just put it away and forget about it. Don't use frozen berries because the texture is too soft.

600 grams small strawberries

900 grams of fresh berries such as blueberries, raspberries, redcurrants or blackcurrants, blackberries and/or mulberries

About 500 grams of granulated sugar

Brandy, cognac, armagnac or eau de vie

Wash a large, heatproof jar, fill it with boiling water and leave for 10 minutes. Wash the lid and put it in a bowl, cover with boiling water and leave for 10 minutes. Pour off the water and leave the jar and lid to air-dry.

Rinse the fruits under cold running water, then lay on kitchen towels and leave to air-dry.

Remove and discard the cores from the strawberries then cut in half. Remove the stems from the currants and mulberries.

Layer the fruit and sugar in a jar, then add enough alcohol to cover the fruit. Cover with the lid and leave at room temperature (but out of the sun) for a week, shaking the jar several times each day to dissolve the sugar. Leave for several months before tasting.