(Makes about 500 g)

Note: This recipe uses raw eggs.

3 sour oranges
175 g caster sugar
2 or 3 sugar lumps
125 g unsalted butter, cut into pieces
4 free-range eggs, well beaten and sieved

Grate the zest from the oranges and put to one side. Rub the sugar lumps over the orange to extract the rest of the oil and flavour and put in a stainless steel saucepan, set over another pan of hot water, together with the rest of the sugar. Halve the oranges and squeeze the juice into the sugar.

Add the pieces of butter and stir until the sugar has almost dissolved and you have a uniform mixture. Gradually beat in the eggs and continue to cook over hot water until the mixture thickens.

This will take anything up to 40 minutes. The process should not be hurried by raising the heat, as you risk the mixture curdling. After about 25 minutes, stir in the orange zest.

I do not like to add it earlier since it takes on a somewhat marmalade-like quality from long cooking, and I like to preserve the sharp, unique, fresh flavour of the bitter orange.

The mixture should lightly coat the back of a spoon before you remove it from the heat. Do not worry if it looks pourable rather than spreadable. The mixture thickens as it cools and the butter firms up. Pour into small, clean jars, allow the curd to cool slightly and then seal the jars, label them and refrigerate.

Cook’s note: You can use the curd to make a number of easy, yet luxurious chilled or iced puddings, such as soufflés, parfaits and ice cream. In each case, the eggs are uncooked.