1 teaspoon cornflour
juice of 2 lemons
2 eggs, lightly whisked
3/4 cup sugar
125g (4 1/2 oz) butter, chopped
very finely grated zest of 1 lemon (optional)
Dissolve cornflour in lemon juice in a small bowl.
Combine eggs, sugar, butter and lemon zest in a small saucepan. Add cornflour and lemon juice and whisk over a very low heat until mixture thickens. Do not allow to boil. remove from heat.
Pour into sterilised jars and seal. Keep in the fridge and use within 2 weeks.