The famous bakery-style vanilla custard slice is sweet, creamy and absolutely delicious. A classic Australian recipe that everyone loves!
If you live in Australia, there's a fair chance that vanilla slice is one of your favourite bakery treats (along with jelly cakes, chocolate caramel slice and jelly slice, of course!).
But if you thought that bakery-bought vanilla slice was good, just wait until you try my simple homemade version!
Australian Vanilla Custard Slice
Vanilla custard slice is a famous Australian sweet slice recipe that's also known as 'custard slice' or 'vanilla slice'. It is similar to a Mille-feuille in France.
It has base and top layers of either puff pastry or Arnotts Lattice biscuits sandwiched with a thick creamy custard and topped with a sweet icing sugar glaze.
This classic old-fashioned slice was made popular by the CWA (Country Womens Association) and is a favourite in bakeries across Australia (including the Beechworth Bakery's famous version!).
Why You're Going To Love This Recipe
This sweet and creamy slice makes the perfect afternoon tea treat:
- simple to make - my version uses Arnotts Lattice biscuits which takes the hassle out of using puff pastry
- easy to cut - by using Lattice biscuits instead of puff pastry, it's so easy to cut the slice. Follow the guide of the outline of the biscuits for perfect slices
- perfect flavour - the 3 layers of crunchy biscuits, thick creamy custard and sweet icing glaze gives this slice the most delicious flavour and texture
What You Need
While this slice is an absolute showstopper, it's actually made from just a few basic ingredients:
For The Slice
- Arnotts Lattice biscuits - these square biscuits are made with layers of sweet flakey 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.
For The Glaze
- 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!
How To Make Vanilla Custard Slice From Scratch
This easy 3 step recipe takes just 15 minutes to make:
Step 1 - Prepare The Custard
Place the custard powder into a saucepan and add enough milk (approximately ¼ cup) to dissolve the powder.
Add the sugar and remaining milk and stir to combine.
Whisk the custard continuously over medium heat until it starts to thicken. Once the custard starts to bubble, continue to whisk for an extra 2 minutes until quite thick.
Cover with plastic wrap (to avoid the custard developing a 'skin') and leave for 20 minutes to cool.
Step 2 - Assemble The Slice
Place 9 Arnott's Lattice biscuits in the base of a lightly greased square 20cm cake tin.
Pour the custard over the top.
Add an extra 9 Lattice biscuits.
Step 3 - Prepare The Glaze
Sift the icing sugar into a bowl, add a small amount of water and the food colouring and mix.
Once the icing is just spreadable (don't add too much water), spread it over the slice and place into the fridge for a minimum of 4 hours (overnight is best).
Cut into slices before serving.
Vanilla Slice Variations
Vanilla custard slice can be made with a few variations:
Puff Pastry
Vanilla custard slice is made using either Arnott's Lattice biscuits or sheets of puff pastry.
While I love how easy it is to use Lattice biscuits, they're not available in all parts of the world - and therefore, puff pastry is a great option!
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 Glaze
Vanilla slice is traditionally topped with a white glaze, a pink glaze or a passionfruit glaze.
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).
How To Cut Custard Slice
By using Arnott's Lattice biscuits, it is SO easy to cut your vanilla slice.
For best results, leave the slice in the fridge overnight before cutting.
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 and store in the fridge.
Recipe FAQ & Tips
How do you cut vanilla custard slice without squashing it?
See my tips above for cutting vanilla slice that's been made with Lattice biscuits (the easiest option!)
To cut vanilla slice that's been made with puff pastry, use a small sharp serrated knife and cut through only the top pastry layer. Then use a large sharp knife to gently press down through the custard and pastry base layer.
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.
How long does this slice last?
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.
Can this slice be frozen?
This slice is not suitable for freezing.
More Classic Slice Recipes
If you love old-fashioned slices, then you're going to fall in love with these delicious classics too...
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Easy Vanilla Custard Slice
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.
Notes
- 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.
Katie
Does anyone know if the lattice biscuits have been discontinued? I tried two supermarkets and couldn’t find them in either.
Lucy
They have been! You can use 2 sheets of cooked puff pastry instead! xx
Dan
Had never heard of the Lattice biscuit mentioned, don’t think we ever had them down here in Tassie, a quick search online shows that Arnott’s discontinued them back in 2021.
Lucy
Hi Dan, yes indeed they did! You can use 2 large sheets of cooked puff pastry instead 🙂
Stefanie Fischer
How to line up the top layer of lattice biscuits so I cut them in proper cubes
Lucy
Hi Stefanie, I find that if you use a 20cm square tin they tend to line up perfectly.
Pam Holko
A lovely recipe. I use it often. I find adding a teas. of gelatine in a tables. of boiling water to the custard helps to slice easily.Lucious vanilla slices. As good as any bought.
Lucy
I'm so thrilled to hear that! Thank you Pam!!