This mixed citrus marmalade recipe, made with oranges, mandarins, and limes, is essentially a lovely fruit jam that's simple to make and tastes complex as heck.
To make a chunky marmalade, combine the whole fruit and water in a pot, cover, and simmer for 1 to 2 hours, until the fruit is tender. Use a slotted spoon to remove the fruit from the liquid and let it cool slightly. Cut the fruit into slices. Pick out as many seeds as you can and toss them in the cooking liquid. (The seeds contain pectin for setting the jam.) Simmer the liquid for another 20 minutes, then strain the liquid and discard the seeds.To make a less chunky marmalade, coarsely chop the fruit, toss it in a pot with the water, cover, and simmer for 1 to 2 hours, until the fruit is tender. Use a slotted spoon to remove the fruit from the liquid and let it cool slightly. Pick out as many seeds as you can and toss them in the cooking liquid. (The seeds contain pectin for setting the jam.) Simmer the liquid for another 20 minutes, then strain the liquid and discard the seeds.
Measure the fruit in cups and add enough strained cooking liquid to make a total of 6 cups (1.5 litres). Return the fruit and liquid to the clean pot. Add the sugar and lemon juice and stir over low heat until the sugar dissolves.
Increase the heat and boil, stirring occasionally to keep the mixture from scorching and skimming foam from the surface as necessary, for 30 to 35 minutes, until the marmalade reaches its setting point. This happens around 220°F (104°C) can be tested by putting a teaspoon of the marmalade onto a chilled plate and observing it. The marmalade is set when it appears firm with a wrinkle on the surface once it cools slightly.
Ladle the hot marmalade into warm sterilized jars and immediately seal the jars. Store in a cool, dark place for up to 12 months. Refrigerate after opening.