Lemon and Pink Grapefruit Marmalade

My eldest son heard about this recipe and the cookbook it came out of, on a Splendid Table podcast, went to the public library, did not pass 'Go', and made this splendid marmalade. * 1 pound lemons (preferably Lisbon), cut into eighths * 1 pound seeded lemons, halved crosswise, each half cut lengthwise into quarters and sliced thinly crosswise * 3 3/4 pounds pink grapefruits * 5 pounds white cane sugar * 2 or 3 extra lemons, to make 5 ounces strained freshly squeezed lemon juice Instructions * Day 1 * 1. Place the lemon eighths in a nonreactive saucepan where they will fit snugly in a single layer. Add enough cold water for the fruit to bob freely. Cover tightly and let rest overnight at room temperature. * Day 2 * 2. Prepare the cooked lemon juice: Bring the pan with the lemon eighths to a boil over high heat, then decrease the heat to medium. Cook the fruit at a lively simmer, covered, for 2 to 3 hours, or until the lemons are very soft and the liquid has become slightly syrupy. As the lemons cook, press down on them gently with a spoon every 30 minutes or so, adding a little more water if necessary. The water level should stay consistently high enough for the fruit to remain submerged as it cooks. * 3. When the lemons are finished cooking, strain their juice by pouring the hot fruit and liquid into a medium strainer or colander suspended over a heatproof storage container or nonreactive saucepan. Cover the entire setup well with plastic wrap and let drip overnight at room temperature. * 4. Meanwhile, prepare the sliced lemons: Place the slices in a wide stainless-steel kettle and cover amply with cold water. Bring to a boil over high heat, then decrease the heat and simmer for 5 minutes. Drain, discarding the liquid. Return the lemon slices to the kettle and cover with 1 inch cold water. Bring to a boil over high heat, decrease the heat to medium, and cook at a lively simmer, covered, for 30 to 40 minutes, or until the fruit is very tender. As the fruit cooks, stir it gently every 15 minutes or so, adding a little more water if necessary. The water level should stay consistently high enough for the fruit to remain submerged as it cooks. Remove the pan from the heat, cover tightly, and let rest overnight at room temperature. * 5. Last, prepare the grapefruits: Cut them in half, squeeze the halves, and strain their juice. Cover the juice and place it in the refrigerator. Put the juiced grapefruit halves in a large nonreactive kettle and cover them amply with cold water. Bring to a boil over high heat, then decrease the heat to medium and cook at a lively simmer for 5 minutes. Drain, discarding the liquid. Repeat this process, then return the blanched grapefruit halves to the kettle and add cold water to cover. Bring the halves to a boil over high heat, then decrease the heat to medium-low and cook, covered, at a lively simmer for 1 to 2 hours, or until the fruit is easily pierced with a skewer. As the grapefruit cooks, press down on it gently with a spoon every 30 minutes, adding more water if necessary. The water level should stay consistently high enough for the fruit to remain submerged as it cooks. When the grapefruit is tender, remove the pan from the heat, cover tightly, and let rest overnight at room temperature. * Day 3 * 6. Place a saucer with five metal teaspoons in a flat place in your freezer for testing the marmalade later.Remove the plastic wrap from the lemon eighths and their juice and discard the lemons. Strain the juice well through a very fine-mesh strainer to remove any lingering solids. * 7. Prepare the grapefruit: Remove the grapefruit halves from their kettle, reserving the cooking liquid. Over a large bowl, use a soup spoon to scoop the flesh from each grapefruit half. Then, take each half and, cradling it in one hand, use the spoon to gently scrape its interior of excess pith and fibers. Repeat with the rest of the halves, going around each one two or three times until its interior is smooth and its rind is a uniform thickness. Cut each grapefruit half into 5 equal strips, then cut each strip crosswise into thick slices and reserve. Strain the scraped pith and fibers, along with the mushy interiors of the grapefruits, back into the cooking liquid, letting them drip for several minutes. Discard the solids. Pour the liquid through a fine-mesh strainer. * 8. In a large mixing bowl, combine the sugar, strained grapefruit cooking liquid, reserved fresh grapefruit juice, reserved grapefruit rinds, cooked lemon juice, fresh lemon juice, and lemon slices and their liquid, stirring well. Transfer the mixture to an 11- or 12-quart copper preserving pan or a wide nonreactive kettle. * 9. Bring the mixture to a boil over high heat. Cook at a rapid boil until the setting point is reached; this will take a minimum of 30 minutes, but may take longer depending on your individual stove and pan. Initially, the mixture will bubble gently for several minutes; then, as more moisture cooks out of it and its sugar concentration increases, it will begin foaming. Do not stir it at all during the initial bubbling; then, once it starts to foam, stir it gently every few minutes with a heatproof rubber spatula. As it gets close to being done, stir it slowly every minute or two to prevent burning, decreasing the heat a tiny bit if necessary. The marmalade is ready for testing when its color darkens slightly and its bubbles become very small. * 10. To test the marmalade for doneness, remove it from the heat and carefully transfer a small representative half-spoonful to one of your frozen spoons. It should look shiny, with tiny bubbles throughout. Replace the spoon in the freezer for 3 to 4 minutes, then remove and carefully feel the underside of the spoon. It should be neither warm nor cold; if still warm, return it to the freezer for a moment. Tilt the spoon vertically to see whether the marmalade runs; if it does not run, and if its top layer has thickened to a jelly consistency, it is done. If it runs, cook it for another few minutes, stirring, and test again as needed. * 11. When the marmalade has finished cooking, turn off the heat but do not stir. Using a stainless-steel spoon, skim off any surface foam and discard. Pour the marmalade into sterilized jars and process--they recommend doing it in the oven.