A batch of vanilla custard slice on a sheet of baking paper on a wooden board. Once sits on a plate in front with a bite taken out
5 from 3 votes

Lemon Vanilla Custard Slice

Prep Time: 7 minutes
Cook Time: 8 minutes
Total Time: 2 hours 15 minutes
Servings: 12 serves
Calories: 378kcal
Author: Marie Roffey
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This classic Australian bakery treat, the Vanilla Custard Slice is a sweet, creamy set-custard between with puff pastry, topped with icing. This recipe has an irresistible tang of lemon and is easy to make at home.
Course: Afternoon Tea, Dessert, Snack, Sweets
Cuisine: Australian, British
Keyword: custard slice, lemon custard slice, vanilla custard slice, vanilla slice

Ingredients

  • 2 sheets puff pastry
  • 1 ½ cups milk
  • 1 1/2 cups thickened (heavy) cream
  • 57 g (1/4 cup) unsalted butter
  • 1 teaspoon vanilla extract
  • 1/2 cup white granulated sugar
  • 1/2 cup cornflour / cornstarch (spooned & levelled)
  • ¼ cup water
  • 1 teaspoon lemon zest
  • 1 ½ tablespoons lemon juice (notes)
  • 4 egg yolks (from large eggs)
  • 1 1/2 cups icing (powdered) sugar
  • 2 tablespoons lemon juice (notes)

Instructions

  • Preheat oven to 200C / 395F / 180C.
  • Line two baking trays and place a sheet of puff pastry on each one. Lay another piece of baking paper on top of each, then place another baking tray on top of each without pressing down.
  • Bake for 20-25 minutes or until golden then transfer to a wire rack to cool.
  • Heat together the milk, cream, butter, vanilla. and sugar a heavy based saucepan over low to medium heat until bubbles just start to appear. Make sure to stir regularly. Turn the heat off.
  • Place the cornflour, water and egg yolks in a large bowl and beat with a handheld beater just until combined and lightened.
  • With the beater on low, slowly drizzle the hot milk mixture into the egg mixture. Don't rush it or you may end up scrambling your eggs.
  • Tip it all back into the saucepan and heat over low-medium heat, whisking constantly, until it thickens. It will get quite thick after 4-5 minutes. It is ready when it starts looking 'bouncy' almost and when dolloping custard on top of itself, it takes a while to settle back into itself. Turn the heat off.
  • Sit an 8x8 inch square baking tin on top of one of the pieces of baked puff pastry. Use a large, sharp knife to cut straight down through the pastry around the base of the pan so you have a square that will fit inside the pan.
  • Repeat with the second sheet of puff then slice this second square into 8, 9 or 12 pieces (whichever size you want to serve).
  • Line the square tin with baking paper, then place the first puff square in the bottom.
  • Pour the custard over the top and level it out with an offset spatula.
  • Place the sliced pieces of the second sheet of puff over the top, butting up to each other.
  • Place in the fridge to set for at least 4 hours (or overnight)
  • At any time, once the custard is cool, you can make the icing.
  • Mix the icing sugar and lemon juice until it forms a smooth paste. Pour then level it over the top of the custard slice, still in the tin. This should set at least 1 hour before serving.

Notes

Equipment used: Handheld beater, 8x8 inch sqare baking tin, whisk and silicone spatula
  1. I use a standard Australian 20ml tablespoon (= 4 teaspoons worldwide)
  2. For best results, you should always weigh ingredients like flour and sugar. Kitchen scales are relatively cheap but if you can’t weigh the ingredients, use the spoon and level method (don’t scoop).

Variations:

  • Leave out the lemon: For a raditional vanilla slice, simply leave out the lemon components and add an extra teaspoon of vanilla to the custard mix. That’s it.
  • Passionfruit icing: Substitute the lemon juice in the icing for passionfruit pulp. You may need a little extra but add it a little at a time so that it’s not too runny.
  • Chocolate: You could use this recipe for my Tim Tam Chocolate Custard Slice for the custard portion and use the puff pastry as mentioned in this one. Dust it with cocoa or top it with a chocolate icing instead (icing sugar, cocoa and milk or water)

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