Step 1

Place butter, sugar, lemon rind and lemon juice in a heatproof bowl. Place bowl over a saucepan of simmering water, making sure the bowl doesn't touch the water. Cook, stirring constantly with a wooden spoon, for 5 minutes or until sugar dissolves. Remove from heat. Whisk in eggs. Return to heat.

Step 2

Cook, stirring with a wooden spoon, for 8 minutes or until mixture thickens and coats the back of the spoon. Remove from heat. Set aside for 5 minutes to cool. Strain into hot, sterilised jars. Secure lids. Refrigerate for up to 1 month.