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An easy vanilla custard slice recipe made with a biscuit base and topped with a classic pink icing! This is just like a bakery-bought vanilla slice!

Easy Vanilla Custard Slice

An easy vanilla custard slice recipe made with a biscuit base and topped with a classic pink icing! This is just like a bakery-bought vanilla slice!
5 from 15 votes
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Course: bars and slices
Cuisine: Australian recipe
Prep Time: 15 minutes
Chilling time: 4 hours
Total Time: 4 hours 15 minutes
Servings: 9 serves
Calories: 309kcal

Equipment

  • Stove-top or Thermomix

Ingredients

  • 200 g Arnotts Lattice biscuits
  • ½ cup (65g) custard powder
  • 2 ½ cups (610g) milk
  • ¼ cup (55g) caster sugar
  • 2 ½ cups (500g) icing sugar mixture
  • 4-5 tbs (50-76g) water (see notes)
  • 1-2 drops pink food colouring

Instructions

Conventional Method

  • Lightly grease the base and sides of a 20cm square cake tin. 
  • Place 9 of the lattice biscuits in a 3X3 grid on the base of the tin (they should fit almost perfectly). Set aside. 
  • Place the custard powder into a saucepan with ¼ cup of the milk. Stir until all of the custard powder has dissolved. Add the remaining 2 ¼ cups of milk and the caster sugar. 
  • Whisking continuously, heat the custard over a medium heat for 5 minutes or until it has started to thicken. Once the custard starts to boil, continue whisking for a further 2 minutes or until very thick. Place a sheet of glad wrap over the custard to stop it forming a 'skin' and allow to cool for 20 minutes. 
  • Pour/spread the cooled custard over the biscuits and top with another 9 biscuits in the same 3x3 grid. 
  • To make the icing, sift the icing sugar into a bowl and add the food colouring. 
  • Add the water 1 tablespoon at a time and stir until you have a smooth paste (that can be spread). 
  • Spread the icing over the slice and place into the fridge for 3-4 hours (overnight is best). 
  • Cut the slice into 9 pieces using the shape of the biscuits to guide you. 

Thermomix Method

  • Lightly grease the base and sides of a 20cm square cake tin. 
  • Place 9 of the lattice biscuits in a 3X3 grid on the base of the tin (they should fit almost perfectly). Set aside. 
  • Place the custard powder, milk and caster sugar into the Thermomix bowl. Cook for 9 minutes, 90 degrees, Speed 4. If the custard is too runny, cook for a further minute.
  • Place a sheet of glad wrap over the custard to stop it forming a 'skin' and allow to cool for 20 minutes. 
  • Pour/spread the cooled custard over the biscuits and top with another 9 biscuits in the same 3x3 grid. 
  • To make the icing, place the icing sugar into a clean and dry Thermomix bowl. Sift by pressing Turbo for 2-3 seconds. Add the pink food colouring and 3 tbs water. Mix for 10 seconds, Speed 6. Scrape down the sides of the bowl and mix for a further 5 seconds. If the mixture is too thick and can't be spread, add 1 more tablespoon and mix again (it should be a thick paste).
  • Spread the icing over the slice and place into the fridge for 3-4 hours (overnight is best). 
  • Cut the slice into 9 pieces using the shape of the biscuits to guide you. 

Video

Notes

RECIPE NOTES & TIPS
Ingredients Info:
  • Arnotts Lattice biscuits – these square biscuits are made with layers of sweet flaky pastry with a sweet sugar glaze. You can buy them from any supermarket in Australia. Alternatively, you can use a sheet of puff pastry on the base and top instead.
  • custard powder – this is a fine powder that is made from thickeners, milk powder and flavouring. When cooked with milk and sugar it turns into a thick vanilla custard. It can be purchased from the dessert aisle of the supermarket (not the chilled section).
  • milk – I recommend using full fat milk as it results in a thicker, creamier custard.
  • caster sugar – this is a fine sugar that dissolves when cooked with the custard powder and milk.
  • icing sugar mixture – this can be bought from the baking section of the supermarket. It is made from a combination of powdered sugar and cornflour. It differs from pure icing sugar in that it sets softer – making it perfect for a pourable glaze.
  • water – only add enough water to make the glaze just spreadable. Too much water will make the glaze too watery and turn the slice soggy.
  • pink food colouring – optional. This gives the icing such a pretty colour. You only need a teeny-tiny drop of food colouring – don’t overdo it.
More Recipe Tips: 
Puff pastry variation - To use puff pastry, place 2 sheets of defrosted puff pastry sheets on a flat tray, brush with egg and bake in a 230 degree celsius oven for 10 minutes. Remove from the oven and set aside to cool. Prepare as per the recipe below – replacing the Lattice biscuits with the cooked puff pastry sheets.
Passionfruit icing - To make passionfruit glaze, omit the pink food colouring and water and replace with passionfruit pulp (use just enough to get a spreadable thick paste).
Thickening the custard - It's important to continue to cook the custard (while continuously whisking) until it is very thick - this will ensure it sets firm.
Cutting the slice - The icing glaze is quite thin and so you can see the outline of the Lattice biscuits underneath. Use a large sharp knife to cut the slice into 9 pieces following the outline of the biscuits as a guide. Remove the slices from the baking tin and place into an airtight container in the fridge.
Storing - Custard slice can be stored in the fridge for 3-4 days. The pastry layers will soften the longer the slice is in the fridge.
Freezing - This slice is not suitable for freezing.

Nutrition

Calories: 309kcal | Carbohydrates: 57g | Protein: 4g | Fat: 8g | Saturated Fat: 3g | Cholesterol: 14mg | Sodium: 150mg | Potassium: 118mg | Fiber: 1g | Sugar: 45g | Vitamin A: 130IU | Calcium: 87mg | Iron: 0.6mg