Serves: Makes eleven one half pint jars of marmalade
- 2½ pounds (6 to 8 medium) oranges, such as Valencia or Cara Cara
- ¾ pound (about 2 large) lemons
- 6 cups cold water
- 20 green cardamom pods, crushed
- 8 cups granulated sugar
Prepare the fruit 12 to 24 hours before you plan to cook and preserve the marmalade. Wash and pat dry all the fruit. Trim and discard the stem ends. Cut the oranges and lemons into quarters and poke out all the seeds with the tip of a paring knife. Reserve the seeds in a small covered container. Using a sharp chef's knife or mandoline, cut all the citrus, including the rinds, into 1⁄16-inch-thick slices. Put the sliced fruit in a large pot, including any juices left on the cutting board. Add the 6 cups of water. Gently press down on the fruit to make sure it is submerged. Cover the pot and set aside at room temperature for 12 to 24 hours. (This softens the rinds and releases the pectin.)
The next day, bring the pot of sliced fruit and water to a boil over medium-high heat. Adjust the heat so the mixture boils steadily without splattering, and cook for 30 minutes. Wrap the crushed cardamom pods and the reserved lemon and orange seeds in a cheesecloth bag tied securely with kitchen twine.
While the fruit is cooking, prepare the preserving jars and bring water to a boil in a water bath canner. Sterilize the jars and lids.
Add the sugar to the fruit mixture and stir until dissolved. Add the cheesecloth bag of cardamom and seeds. Continue to cook the marmalade at a steady boil until it reaches the gel stage or reaches 220°F on a candy thermometer, 30 to 40 minutes longer.
Remove the cheesecloth bag from the marmalade, pressing any liquids back into the pan.
Remove the marmalade from the heat. Using a wide-mouth funnel and filling one jar at a time, ladle the marmalade into hot, sterilized jars, leaving ½ inch headspace. Remove any air bubbles by running a long wooden utensil, such as a chopstick or wooden skewer, between the jar and the marmalade. Wipe the rims clean. Seal according to the manufacturer's directions. Process the jars in a boiling water bath for 10 minutes, and then turn off the heat. Wait 5 minutes, and then lift the canning rack and, using a canning jar lifter, transfer the jars to a towel-lined, sturdy rimmed baking sheet and let them rest. Check the seals, wipe the jars, and label. Note: Here's an easy way to check whether the marmalade is set. Put a small plate in the freezer. When the marmalade looks thickish and a bit gelled, put a small amount of the marmalade on the frozen plate and return it to the freezer. After a couple of minutes, run your finger or a spoon down the center and see if it stays separated and is a bit wrinkled. If so, it is done.
Storing: Store the jars in a cool, dark place for up to 1 year.