Easy Lemon Custard Slice by Sugar Salt Magic
5 from 1 vote

Easy Lemon Custard Slice

Prep Time: 7 minutes
Cook Time: 8 minutes
Total Time: 2 hours 15 minutes
Servings: 9 serves
Author: Marie Roffey
Homemade custard with a lemon twist, sandwiched between flaky biscuits
Course: Afternoon Tea, Dessert, Snack, Sweets


  • 18 lattice biscuits
  • 1 ½ cups milk
  • 30 g butter
  • 1 teaspoon vanilla extract
  • 1/3 cup caster sugar
  • 1/3 cup cornflour
  • ¼ cup water
  • 3 egg yolks
  • 2/3 cup lemon curd
  • 1 cup icing sugar (confectioners / powdered)
  • 1 teaspoon lemon zest
  • 1 ½ tablespoons lemon juice (see notes)


  • Line a square baking tin with baking paper or plastic wrap. Arrange 9 of the lattice biscuits, in rows of 3, on the bottom of the pan, glazed side down.
  • Pour the milk into a heavy based saucepan, and add the butter, sugar and vanilla, then heat on very low heat until steaming, stirring regularly.
  • While the milk mixture is heating, mix together the water and cornflour until smooth. Pour it into a large bowl (or the bowl of a stand mixer) and add the egg yolks, then beat on high until light and pale yellow.
  • Once the milk mixture is steaming, remove from heat. Turn the stand mixer down to low-medium and pour the milk mix in a slow steady stream into the egg mix. Don’t pour it too quickly or the heat will scramble the eggs.
  • Once all the milk is added to the eggs, return the entire mix to the saucepan. Heat over low heat, stirring with a balloon whisk constantly, until it gets very thick. This will happen quite suddenly after about 5 minutes or so, so it’s important to keep gently whisking increasing intensity as it gets very thick. You will end up with lumpy custard if you don’t.
  • When the custard is very thick, remove from the heat and add the lemon curd. Whisk until everything is smooth and well combined then pour and spread over the bottom layer of biscuits. Top with the other 9 biscuits in the same pattern and place in the fridge while making the glaze.
  • Mix together the icing sugar, lemon zest and lemon juice and pour over the top of the slice. Spread evenly.
  • Allow to set in the fridge for 2-3 hours before slicing and serving.


I use an Australian 20ml tablespoon