Prep time 15 minutes
Cook time 2 hours 20 minutes
Makes about 5 cups
medium navel oranges (about 2 1/4 pounds total)
- 2 quarts
- 5 cups
Wash and scrub 4 medium navel oranges and 2 medium lemons.
Cut the ends off the oranges and discard. Halve the oranges and juice through a fine-mesh strainer fitted over a large saucepan to catch seeds and pulp (about 1 cup juice). Halve the lemons and juice through the strainer into the saucepan (about 1/3 cup juice). Place the juiced lemon shells in the strainer.
Flip each orange shell inside out. Peel away the flesh and membranes with your fingers and add them to the strainer. Cut each orange shell into quarters and place in a food processor fitted with the blade attachment. Pulse into 1/2-inch pieces, about 7 (1-second) pulses. (Alternatively, use a sharp knife to slice the orange peel into thin strips.) Add to the saucepan.
Transfer the contents of the strainer onto the center of a large piece of muslin cloth or double layer of cheesecloth. Pull up the four corners to the middle to form a pouch. Tie the pouch shut with kitchen string and add to the saucepan.
Add 2 quarts water to the saucepan. Cover, and let soak at room temperature overnight.
The next day, uncover and bring the mixture to a boil over high heat. Reduce the heat to low and simmer gently for 2 hours. Meanwhile, place a plate in the freezer (you’ll need this to check for doneness).
Remove the pouch and squeeze it between two slotted spoons or tongs to extract as much liquid as possible. Discard the pouch.
Clip a candy or deep-fry thermometer to the side of the saucepan. Add 5 cups granulated sugar and stir until dissolved, skimming off any foam that rises to the top. Stop stirring and let the mixture heat up to 220ºF, about 15 minutes. Adjust the heat as needed to simmer at this temperature for 5 minutes.
Turn off the heat. Test the marmalade by smearing a spoonful onto the frozen plate. Tilt the plate — the marmalade is ready if it’s a soft gel consistency that moves slightly and forms a skin on top. It may run down the plate at first, but as long as it forms the gel straight away, then it’s ready. If it’s thin and runny, continue simmering and re-checking every 10 minutes.
Let the marmalade cool for 15 minutes. Give it a stir to redistribute, then ladle into mason jars or storage containers. Seal and refrigerate until set, 5 to 24 hours.
Storage: Marmalade will keep in an airtight container in the refrigerator for up to 2 months.
Freezing: You can also freeze this marmalade for up to 6 months, just be sure to leave 1/2-inch of room at the top of the jar so the jam can expand while freezing.