This is delicious as a spread for toast or scones, to sandwich together a sponge cake or as the filling for powder puffs. It keeps for weeks if well sealed and refrigerated after opening.
- Whisk egg yolks and sugar until well combined but not frothy.
- Tip into a heavy-based non-reactive saucepan and add butter,cornflour, zest and juice.
- Stirring constantly, bring to simmering point over a medium-high heat (about five minutes).
- As soon as bubbles appear, remove from heat, still stirring. Allow to cool.
- Transfer to sterilised jars and seal.
- Makes 2 cups.