This recipe is the result of tweaking and adapting from many recipes over the years. In this version, I cut my peels rather thickly, as I like the pungent orange flavor. If you prefer a milder, sweeter flavor and softer texture, cut the peels very finely. Seville oranges are the best ones for marmalade as they have a naturally high level of pectin—the ingredient that helps the marmalade set, naturally found in oranges, concentrated in the peel—so use those if you can find them. Makes about 10 8-ounce jars 10 medium oranges, preferably Seville 4 lemons 16 cups water 5 pounds white granulated sugar Wash the oranges and lemons. Cut them in half lengthwise, removing any seeds, and then slice them into 1/8-inch-thick pieces. Place the orange and lemon slices in a large stockpot and add the water. Bring the mixture to a boil. Remove from the heat and add …