Remove the wax from the oranges by placing them in a sieve and pouring over boiling water. Then use a potato scrubber and scrub under cold running water. Then dry.
Zest and juice the oranges (mine yielded 100 mls juice).
Place the sugar, butter, juice and zest in a pan over a low heat.
Stir until the sugar has dissolved and butter melted.
Whisk in the beaten egg over a medium heat and bring to the boil.
Boil for one minute, whisking continuously or until the mixture coats the back of a spoon (it will thicken further on cooling).
Pot up into hot sterilised jar/s (see notes).
Makes about 300 mls of curd.
Store in the fridge where it will keep for a few weeks.