Vanilla custard slice: it’s creamy, rich, indulgent and also easy to make. This bakery treat is a classic Australian recipe and possibly our own take on a French mille feuille is mind-blowingly good. Just imagine a layer of creamy, soft-yet-set custard sandwiched between two layers of buttery, flaky puff pastry, all topped off with a sweet icing. Love at first bite!
I couldn’t resist the temptation to add a little zing of lemon to my recipe but you can just as easily leave it out for a classic vanilla slice.
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What is Vanilla Slice?
Similar to the French mille-feuille but with fewer layers, the traditional custard slice has a thick, sweet custard set between two layers of baked puff pastry. The custard is very similar to a the French creme patissiere but a little thicker so that it can be sliced through.
Seemingly originating in Australia (though many other countries like the UK and New Zealand adore this classic too), vanilla slice (also often called custard squares) is most often topped with a white vanilla icing. Sometimes the icing is pink or if you’re really lucky, you’ll find one with passionfruit icing. I’ve recreated both here but for mine, passionfruit is the best – the tartnes of the passionfruit just sets the whole creamy sweet treat alive.
With 3 layers of goodness, this recipe is actually a pretty simple one and luckily for us, it’s very easy to make at home.
How to make it
- You’ll start by baking 2 sheets of pre-rolled puff pastry sheets in the oven until golden.
- The pastry sheet is cut to size to fit into an 8×8 inch square baking tin. This is a simple matter of placing the tin on top of the baked pastry (once it has cooled) and using a sharp knife to cut through it.
- The custard made totally from scratch is a mixture of milk, cream, sugar, butter and vanilla that is heated just until the first bubbles start to appear.
- This gets slowly drizzled into a mixture of egg yolks, water and corn flour whilst continuously beating.
- It all gets added back to the saucepan and whisked slowly over low-medium heat until you have a nice, thick and smooth custard. The custard will look almost bouncy when it’s ready and it will dollop off the whisk and not merge straight into itself again.
- Layer it up – line the square baking tin with baking paper and place one piece of the baked puff pastry in the bottom. Whisk the lemon juice and zest into the custard then pour it over and level it out. Cut the second sheet of pastry into 8 or more even pieces and lay them on top – cutting it at this stage really helps make it easier to cut through the whole slice later.
- After letting it set for a good 4 hours (or overnight is even better), just make a simple 2 ingredient icing and pour it over the top.
Custard slice recipe tips and tricks
- Keep the puff pastry flat while baking: To keep the puff pastry from puffing up too much, sit a baking tray on top of them as they bake. This will result in flatter but still super flaky puff.
- To cut the cooked puff pastry: A large chefs knife pressed directly down is the way to go. Don’t use a sawing motion or you’ll just be left with a flaky pastry mess.
- Use a heavy based saucepan: I use them for everything but especially when making delicate desserts and candies, a heavy based saucepan is a lifesaver. It distributes the heat more slowly and evenly so they don’t burn or split.
- Make sure to temper the eggs: Tempering eggs means to slowly bring their temperature up to match the cooked component so they stay smooth and liquid rather than scrambling. It’s easy don’t worry – just make sure to slowly drizzle the hot liquid into them whilst constantly beating / mixing.
- Pre-cut the top layer of pastry: I like to pre-cut my top pastry layer into the sizes I will cut the slices once it’s set. It’s much easier to cut slices this way. If you don’t pre-cut it, I find the custard layer can be squished as you’re trying to cut it later.
- Go easy with liquid in the icing: In my icing, I use lemon juice to complement the lemon flavour in the custard but you can use just water or milk. Add a little at a time as it can become too runny very easily. It needs to be quite thick so that it takes at least 10 seconds to settle into itself again when you lift the spoon out.
Variations – make it your own!
- Leave out the lemon: If you’re a purist and / or want that traditional vanilla slice, simply leave out the lemon components and add an extra teaspoon of vanilla to the custard mix. That’s it.
- Passionfruit icing: Passionfruit icing is absolutely lovely and works well with the both the vanilla and lemon varieties of this slice. 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 like mine was in these pics. Still indulgent and delicious though. Passionfruit pulp is often sold in the freezer section or tinned fruit section if you can’t find fresh.
- Chocolate: You could use this recipe for my chocolate meringue pie 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)
- No icing: simply dust the top with icing sugar at the time of serving if you prefer
- Lattice biscuits: You can swap the puff pastry with lattice biscuits. This will be even easier to make but not as easy to eat.
Vanilla custard slice is not suitable for freezing. It does, however, keep in the fridge well for 3-4 days.
Absolutely nothing. Custard slice and vanilla slice are simply two names for the same dessert.
Custard slices are made of two layers of puff pastry with a thick custard sandwiched between them and an icing or glaze on top. The custard is similar to creme patissiere (pastry cream) but thick enough to slice through.
Bavarian slice differs a little from custard slice or vanilla slice in that it has an extra layer of puff pastry with jam sandwiched between two of them then the layer of custard and another layer of puff pastry. Bavarian slice also has a two tone icing with a chocolate icing swirled through the vanilla icing.
Did you try this vanilla slice recipe?
Leaving a rating and comment below the recipe is so helpful!
- 2 square sheets of puff pastry
- 1 ½ cups whole milk
- 1 ½ cups thickened cream (heavy cream)
- 57 g unsalted butter (2oz / ¼ cup)
- 1 teaspoon vanilla extract or vanilla bean paste
- ½ cup white granulated sugar (100g / 3 ½ oz)
- ½ cup cornflour (US cornstarch) (spooned & levelled)
- ¼ cup water
- 1 teaspoon lemon zest, optional
- 1 ½ tablespoons lemon juice, optional (notes)
- 4 egg yolks, from large eggs
FOR THE ICING
- 1 ½ cups icing sugar (powdered sugar)
- 2 tablespoons lemon juice (notes)
For best results, always weigh ingredients where a weight is provided
- Place the puff pastry sheets onto the tray/s. Lay another piece of baking paper on top of each, then place another baking tray on top of each without pressing down – this will hlep to keep it flat as it bakes.
- 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, lemon zest, lemon juice 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.
- Return it all to 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.
- 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.
- Please take a moment to leave a comment & rating. It's appreciated and so helpful.
- Tablespoons: I use a standard Australian 20ml tablespoon (equal to 4 teaspoons). Check yours before measuring.
- 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).
- Leave out the lemon: For a traditional 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 chocolate custard recipe from my chocolate meringue pie, in place of the vanilla custard. Dust it with cocoa or top it with chocolate icing instead (icing sugar, cocoa and milk or water)
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