4 medium navel oranges (1 1/2 lb/680 g) 4
2 medium lemons (8 oz/225 g)
water
3 3/4 cups sugar 750 g

Day One

Quarter oranges lengthwise. Cut each quarter in half through the middle to remove seeds. Cut these pieces into coarse dice by hand.

Treat the lemons the same way. Cut the pieces into slightly finer pieces.

Measure the combined fruit pulp and pour it into a mixing bowl. Add an equal volume of cool water. Cover the bowl with plastic wrap and let it stand at room temperature overnight.

Day 2

Bring the marmalade base to a boil in a heavy, nonreactive 4-quart pot. Reduce heat to an active simmer and cook, uncovered, until it is reduced to 4 cups/1 L.

During the last 10 minutes of this reduction, warm the sugar in a preheated 250F/120C oven for 10 minutes.

Begin adding the sugar 1/2 cup/125 mL at a time to the reduced mixture, allowing it to return to the boil after every addition before adding more. Allow the marmalade to boil until it reaches the jell temperature, which is 8F/4.4C above the boiling temperature measured on your candy thermometer. This will take 10 to 15 minutes.

Off the heat, skim the surface and let marmalade sit in the pot for 5 minutes. Stir down the fruit pieces and pour the marmalade into hot, sterilized jelly jars.