Classic Seville Orange Marmalade

Scrub oranges and lemon; cut off stem and blossom ends and any blemishes. Cut in half crosswise; squeeze out juices, reserving pulp and seeds. Strain through sieve into Dutch oven.

Pull out membranes from peels; place along with reserved pulp and seeds on 15-inch (38 cm) square of double-thickness fine cheesecloth. Bring up sides and tie with string; add to pan.

Halve orange and lemon peels; cut crosswise into paper-thin strips. Add to pan.

Add 8 cups (2 L) water; bring to simmer over medium heat. Simmer, stirring often and pressing bag to release pectin, until peel turns to mush when pressed between fingers, 2 to 2-1/2 hours.

Remove bag and let cool; squeeze juice into pan. Mixture should measure 7 cups (1.75 L); if not, add water or boil until reduced.

In clean Dutch oven, bring sugar and fruit mixture to full rolling boil, stirring. Boil vigorously, stirring constantly, until free of foam, thickened and at gel stage, 12 to 15 minutes.

Using funnel, fill hot 1-cup (250 mL) canning jars, leaving 1/4-inch (5 mm) headspace. Cover with prepared lids. Screw on bands until resistance is met; increase to fingertip tight.

Boil in boiling water canner for 10 minutes.