Vanilla Custard Slice

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

While this slice is an absolute showstopper, it's made from just a few basic ingredients in 4 easy steps.

If you live in Australia, there's a fair chance that vanilla slice is one of your favourite bakery treats (along with chocolate hedgehog, jelly slice, chocolate caramel slice, and jam tarts, of course!)

But if you thought that bakery-bought vanilla slice was good, just wait until you try my simple homemade version..... it's totally irresistible!

Australian Vanilla Custard Slice

Vanilla custard slice is a famous Australian sweet slice recipe that's also known as 'custard square' or 'vanilla slice'. It's similar to a Mille-Feuille in France.

This vanilla slice has a thick creamy custard filling sandwiched between a base layer and top layer of flaky puff pastry, and then topped with a sweet icing 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 dreamy slice makes the perfect afternoon tea treat, or even dessert!

• Simple to make - whilst it may look a little complicated it's actually as simple as can be - made using pre-bought pastry sheets, and custard powder instead of an egg custard.
• Always a favourite - vanilla custard slice has been around FOREVER and still is a most popular classic - and this homemade version takes it to another level!
• Budget friendly ingredients - for such an elegant looking slice, it can be made with very inexpensive and basic baking ingredients (and no eggs, no butter).
• Perfect flavour combo - the base and filling of vanilla custard slice are not too sweet, and therefore the sweet glaze is just the 'icing on the cake'!
• Conventional and Thermomix - both simple methods are included in the post and recipe card.

What You Need

Chances are, if you have a couple of sheets of puff pastry and a packet of custard powder at home, you may have everything else required to make this easy homemade vanilla custard slice right now!

Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method!

For The Slice

• Puff pastry - just 2 sheets required, defrosted.
• Custard powder - has a powdery consistency like cornflour, and is made from thickeners, milk powder and flavouring. When cooked with milk and sugar it turns into a thick creamy vanilla custard. It can be purchased from the dessert aisle of the supermarket (not the chilled section). You can also make your own.
• Milk - I recommend using full fat milk as it results in a thicker, creamier custard.
• Caster sugar - also known as superfine sugar; caster sugar dissolves easily when cooked with the custard powder and milk.

For The Glaze

• Soft icing sugar mixture - 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 this sweet pourable glaze.
• Water - only add water a little at a time, just enough to make the glaze spreadable. Too much water will make the glaze too runny, and soften the pastry on top, which you want to stay crispy and flaky.
• Pink food colouring (optional) - this gives the icing such a pretty colour. You really only need a teeny-tiny drop of food colouring - don't overdo it!

Equipment Required

Besides a mixing bowl for the icing glaze, the only baking equipment required for vanilla custard slice is:

• Several flat baking trays - to bake the puff pastry.
• 20cm square baking tin - greased and lined with baking paper.
• Saucepan and stovetop, or Thermomix (optional).

Step By Step Instructions

Here's how to make this easy 4 step vanilla custard slice from scratch:

Note: Scroll to the recipe card at the bottom for the ingredients quantities and full detailed method!

Step 1 - Bake The Puff Pastry

Preheat the oven to 180 degrees celsius (fan-forced).

Place the pastry sheets on flat baking trays lined with baking paper. Use a fork to prick holes all over the pastry.

Add an extra sheet of baking paper on top of each pastry sheet and then place an extra baking tray on top as a weight.

Bake for 20-25 minutes or until golden. Allow pastry sheets to cool completely on a wire rack.

Step 2 - Make The Custard

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 and 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.

If using a Thermomix: 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 one minute.

Place a sheet of glad wrap over the custard to stop it forming a 'skin' and allow it to cool for 20 minutes. 

Step 3 - Assemble The Slice

Grease and line the 20cm square baking tin with baking paper (allowing it to overhang).

Place the square baking tin on top of the cooked pastry sheets and use a serrated knife to carefully trim the sheets to the size of the tin.

Place one of the pastry sheets in the base of the tin.

Spread the cooled custard over the pastry.

Gently lay the extra sheet of cooked and trimmed puff pastry on top.

Step 4 - Make The Glaze

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 and thick paste (that can be spread). 

If using a Thermomix: 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 of water and mix again (it should be a thick paste).

Spread the icing over the top layer of pastry and place the tin into the fridge for 3-4 hours (overnight is best). 

To cut vanilla custard slice, use a small, serrated knife to cut through the top pastry sheet before using a large, flat knife to press down firmly to cut into slices.

Expert Tips

Vanilla custard slice is surprisingly so very simple to make, and the results are well worth it - it's certainly high on my deliciousness scale!

• Use a fork to prick holes over each pastry sheet before baking, to make it extra crispy.
• Bake each pastry sheet between two sheets of baking paper and two baking trays to cook flat and avoid it puffing up.
• It's important to continue to cook the custard (while continuously whisking) until it is very thick - this will ensure it sets firm.
• Glaze - only add water a little at a time, just enough to make the glaze spreadable. Too much water will make the glaze too runny, and soften the pastry on top which you want to stay crispy and flaky.
• Pink food colouring – optional. You really only need a teeny-tiny drop of food colouring – don’t overdo it!
• Storing - vanilla custard slice can be stored in the fridge for 3-4 days, however the pastry layers will soften the longer the slice is in the fridge.
• Freezing - this slice is not suitable for freezing.

FAQs

Whether you call it vanilla custard slice, or custard squares, whether you glaze it pink, white, or even passionfruit flavoured, I'm sure you'll love it, right down to the very last lick of sweet, sticky glaze!

Related Recipes

If you're like me, you probably grew up with these bakery favourites - and they're still as popular and irresistible as ever! It's sort of nice that some things just never change....

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