- Use a sharp knife to slice away both ends of the oranges, then cut away all the peel and pith in sections from top to bottom, cutting around the flesh just under the pith. Slice the flesh into thin rounds, then quarter and put in a mixing bowl with any juice; discard any seeds. Very thinly slice the skin and pith (including the ends) widthways into short slivers and add to the bowl.
- Cover with 600ml water and put a small plate inside the bowl to keep the fruit submerged. Cover with clingfilm; refrigerate overnight.
- The next day, put a small plate in the freezer. Tip the contents of the bowl into a large, wide saucepan. Crack the cardamom pods and add the seeds to the pan (discard the pods). Bring to the boil over a medium-high heat, then simmer very gently for 1 hr, without stirring, until the peel is very soft. Once or twice during cooking, poke down any bits of orange that rise up.
- Stir in the sugar and bring to a gentle simmer. Cook for 40-60 minsover a low heat, without stirring, until syrupy, very shiny, a little foamy and reduced by ⅔. When it’s ready, the marmalade should read 105°C on a sugar thermometer. If you don’t have one, spoon a little marmalade onto the frozen plate: it should start to set within 5 mins and form a skin that wrinkles when pressed. If it doesn’t, continue to simmer, checking every 10 mins.
- Remove from the heat, stir in the lemon juice and mix well. Spoon into hot, sterilised jars*, screw on the lids, then leave to cool to room temperature before storing.
Get ahead: Once opened, store in the fridge for up to 2 months.
Tip: Leftover citrus peel can help set preserves and jams, instead of adding extra pectin. Wrap the membranes and pith in muslin cloth and simmer with the fruit. Remove, squeezing out the juice, before adding sugar.
See more Seasonal recipes
*To sterilise glass bottles, wash in hot, soapy water and rinse well. Dry in the oven for 15-20 mins at gas 1, 140°C, fan 120°C until hot and completely dry. Boil rubber seals for 10 mins, then leave to dry.