2 min read

Custard Square

Custard Square
Custard Square with a feathered chocolate icing

This is a perfectly delicious custard square recipe - unconventional, but absolutely fool proof!

Custard Square or Vanilla Slice is a creamy vanilla infused custard sandwiched between flaky puff pastry or filo pastry.

In this recipe we ice it with a simple white icing and then feather through some chocolate icing to add to the presentation. It is also delicious with desiccated coconut sprinkled on top of the icing or a generous drizzle of passionfruit.

Make it a day in advance to allow the flavours to develop, it's tastier the next day.


  • 1 packet ready rolled flaky puff pastry
  • 40g (1.4 oz) flour
  • 40g (1.4 oz) cornflour or cornstarch
  • 15g (0.5 oz) custard powder (See below for how to make this)
  • Pinch of salt
  • 130g (4.5 oz) sugar
  • 65g (2.3 oz) cold tap water
  • 665g (23.4 oz) milk
  • 30g (1 oz) butter
  • 1 egg yolk
  • 1 vanilla bean, scraped


  • Pre-heat oven to 200 degrees Celsius (400 degrees Fahrenheit).
  • Cut pastry roll in half and put each half onto a baking tray.
  • Dock the pastry all over.
  • Bake until puffed up and golden.
  • Remove from the oven and squash down with a spatula. Leave to cool on wire racks.
  • Put the flour, cornflour, custard powder, salt and sugar into a microwave safe bowl.
  • Add the water and whisk together until smooth.
  • Add the milk and whisk until smooth.
  • Add the butter and scraped vanilla bean and microwave for 2 minutes on high power.
  • Remove from the microwave and give it a good whisk.
  • Return to the microwave and cook for another minute, then whisk.
  • Repeat this until the custard has substantially thickened up.
  • Add the egg yolk, whisking very quickly so that your egg doesn't cook.
  • Return to the microwave for another minute, then whisk and pour onto the pastry sheets (smooth side down)
  • Sandwich the sheets together and put the custard square into the fridge to set and cool.
  • To make the icing, mix icing sugar and boiling water together until a smooth spreadable consistency. You might need to add more water, or if it's too runny add more icing sugar.
  • Pour onto the top layer of custard square and carefully spread it all over.
  • Cut using a serrated bread knife and remember to wipe your knife clean in between each cut.

Custard Powder


  • 1 cup milk powder
  • 1/2 cup cornflour or cornstarch
  • 1 1/2 Tablespoons sugar or vanilla sugar
  • Yellow food colouring optional if you want to light yellow tinge


  • Blend it all together in a food processor for about 20seconds.

This will keep in an airtight container for as long as the use by date on the milk powder.