You will need a dozen good-sized oranges, sugar (to be measured later) and 2 lemons. Oranges with bitter skin are considered the best, such as Seville or Sicily oranges.
Cut oranges in half, remove the peel, and boil covered in water until tender.
Chop into small pieces, add the pulp and juice of the oranges (carefully removing all the white skin), and the juice and grated skin of two lemons. Thin slices may be added for decorative effect.
Weigh the contents of the saucepan and stir in an equal weight of granulated sugar. Boil until clear (approximately 20-30 minutes.
Ladle the hot marmalade into hot sterilized jars; adjust lids and process pints in a boiling water bath for 10 minutes.
Eighteen good-sized oranges make about 4 quarts of marmalade.