Citrus Marmalade

From the garden

• 2 lb citrus (any mix: Seville or sweet oranges, lemons, kumquats, or any homegrown citrus you have), scrubbed well · a mix of sweet and tart fruit makes the best marmalade; include at least one lemon

From the pantry

• 6 cups granulated sugar

1. Halve the fruit through the equator, flick out the seeds, and tie the seeds in a square of cheesecloth: they're loaded with natural pectin. Slice the fruit, peel and all, into paper-thin half-moons; a sharp knife and patience now mean silky peel later.
2. Combine the sliced fruit, seed bundle, and 6 cups of water in a wide, heavy pot. Simmer uncovered 30–40 minutes, until the peel is completely tender: a strip should mash between two fingers. (For extra body, rest the pot overnight at this point; it deepens the pectin extraction.)
3. Fill a boiling-water canner and bring it to a simmer; keep 6 half-pint jars hot in the water and prepare the lids.
4. Fish out and discard the seed bundle, pressing it against the pot side first. Add the sugar, stir until dissolved, and boil briskly, stirring more often as it thickens, until it reaches the gel stage: 220°F at sea level (always 8°F above the boiling point of water at your altitude). Confirm with the plate test: a spoonful on a frozen plate should wrinkle when pushed after a minute.
5. Ladle the hot marmalade into the hot jars leaving 1/4 inch of headspace, wipe the rims, and screw the lids on fingertip-tight. Process in boiling water covering the jars by 1–2 inches for 10 minutes; add 5 minutes at 1,001–6,000 feet, 10 minutes above 6,000 feet.
6. Rest 5 minutes, lift the jars onto a towel, and cool undisturbed 12–24 hours before checking the seals. The set firms fully over the first week.