Orange Marmalade

Step 1

Rinse the oranges under hot water. Quarter the oranges lengthwise; slice crosswise as thinly as possible with a sharp knife.

Step 2

Bring the orange slices, orange and lemon juices, and 6 cups water to a boil in a large nonreactive saucepan over medium-high heat. Reduce heat to medium-low. Simmer until the orange peels are translucent and tender, about 1 1/2 hours.

Step 3

Stir in the sugar. Bring the mixture to a boil over medium-high heat, stirring constantly, until the sugar is dissolved. Continue cooking, stirring often and skimming foam from the surface with a slotted spoon, until the mixture is set and registers 220°F on a candy thermometer, about 15 minutes. (To test if the marmalade has set, place a small amount on a well-chilled plate. Press gently with your finger; the marmalade should wrinkle. If it doesn’t, continue to simmer, 5 to 10 minutes more. Test again; repeat as needed.)

Step 4

Let cool, then transfer to an airtight container. Marmalade can be refrigerated up to 1 month. (Alternatively, transfer the marmalade to sterilized canning jars and process according to the jar manufacturer’s instructions.)