Morabba-ye albaloo

Step 1: Rinse the 2 ¼ lb sour cherries, pull off the stems and pit them over a bowl to catch the juice.

Step 2: Layer the cherries and their juice with the 1 ¾ lb white sugar in a wide, heavy pan, cover and leave overnight (or at least 6 hours) until the sugar has mostly dissolved into a red syrup.

Step 3: Sterilise the jar and lid: wash in hot soapy water, rinse, then set the jar upside down in a 250°F oven for 10 minutes (or boil jar and lid for 10 minutes). Let it cool and dry completely; jar, lid and every spoon you use must be bone dry. Use four 350 ml jars; put the clean lids in a pan of just-boiled water.

Step 4: Set the pan over a medium heat and bring slowly to the boil, shaking the pan rather than stirring so the cherries stay whole, about 10 minutes.

Step 5: Skim off the pink foam, lower the heat and simmer gently for 15–20 minutes, until the cherries look translucent and the syrup coats a spoon.

Step 6: Add the 2 tbsp lemon juice and the 1 tsp rosewater if using and simmer 2 more minutes. Test a drop on a cold plate: it should wrinkle slightly when pushed.

Step 7: Ladle the hot jam into the hot, sterilised jars.

Step 8: Water-bath for room-temperature storage: fill the hot jars to 1 cm from the top, wipe the rims, close, stand them on a rack in a deep pan of water that covers them by 3 cm, bring to a rolling boil and boil for 10 minutes (add 1 minute per 300 m above sea level). Lift out and cool undisturbed; the lids should be pulled down. Any jar that does not seal goes in the fridge.

Step 9: Sealed jars keep in a cool, dark cupboard for a year; once opened, keep in the fridge for up to 2 months and use a clean, dry spoon. Throw it away if you see mould, if it fizzes or smells of alcohol, or if a lid has bulged or leaked.