Watermelon-Rind Preserves

A one-to-one preserve of the sort every put-up shelf once held, written for cooks who already knew how to trim a melon rind. The gaps are all in the preparation and the finish.

• Preparing the rindOnly the pale inner rind is used: pare off every scrap of green skin and cut away all the pink flesh, then dice the white layer into half-inch pieces. Green skin stays tough and bitter no matter how long it cooks.
• The overnight standSugar and rind left together draw out a syrup by osmosis and firm the rind so it holds its shape. Cover the bowl and leave it at room temperature or, in warm weather, in the refrigerator; by morning the sugar should have drawn out a quantity of liquid in the bottom of the bowl.
• Ten tablespoons of orange peelingsThis means the peel itself, zest and white pith, ground fine. A food processor pulsed in short bursts stands in for the meat chopper. Use unwaxed or well-scrubbed oranges, since the peel carries all the flavor here.
• Cook till clearThe hinge of the recipe. Simmer gently, uncovered, stirring now and then, until the dice turn translucent all the way through and the syrup runs thick and gold. This can take an hour or considerably more over low heat; boiling hard scorches the sugar and turns the color brown rather than yellow.
• Judging the syrupA jelly thermometer at 220F, or a spoonful that sheets rather than drips, means the syrup is set. Pull it slightly short if you like a looser preserve, since it thickens further on cooling.
• Yield and keepingThe recipe gives no yield and no sealing instructions: refrigerate and use within a month, or process in jars following a current tested canning procedure.
• For crisper rindMany cooks of the period soaked the diced rind overnight in salted water, or in pickling lime, before the sugar went on. Neither step is in this version, and the result will be tender rather than crunchy.