Passionfruit Vanilla Slice

by Jessica Nguyen

Makes- 1 big rectangle slab, approx 27cm x 18cm. You can cut 8 slices or 16 smaller slices.
Ingredients- 9
Cooking Time- 2.5 hours, excluding overnight chilling/setting time
Skill Level- Medium, plus some patience and delicate handling

Ingredients

Puff Pastry

  • 1 box (375g, 1 x 27cm x 36cm ready rolled sheet) of Careme frozen puff pastry, thawed. Please note, I’ve based my whole recipe on using a whole sheet of this so if you end up using another brand (most supermarket puff pastry brands come as squares) know that that the dimensions of your slice and the ratio/volume of custard to pastry will differ to how mine looks. I highly recommend using this brand where possible as it’s the best quality, but it still can work with any other frozen puff pastry.

Custard


Icing

For a traditional vanilla slice: ¼ cup of icing sugar

For a Passionfruit icing:

  • Pulp of 3 passionfruit
  • 350g (approx 2 cups) of icing/powdered sugar

Equipment

  • Two sheet pans- ideally the same size that can nest on top of each other and ideally with a wire rack that you can assemble the vanilla slice on later. I use these sheet pans with a wire rack for this recipe.
  • Baking paper
  • Whisk
  • Silicone spatula
  • Mixing bowls
  • Pot
  • Sharp, serrated bread knife

Method

Watch the process

Baking the Puff Pastry

  1. Preheat your oven to 190 degrees celsius fan forced.
  2. Roll out your puff pastry sheet onto a chopping board and use a ruler and knife to cut straight down the middle so you now have two puff pastry rectangles. They should be 18cm in length and 27cm in height. 
  3. Line one of your sheet pans with baking paper and carefully place the two sheets of puff pastry onto the pan, allowing a few centimetres gaps around the edges of each sheet. Place another sheet of baking paper over the top of the puff pastry and cover with the other sheet pan. Your puff pastry should be in between a layer of baking paper and the two sheet pans. 
  4. Place a heavy oven safe baking dish on top of the sheet pans to weigh down the puff pastry as it will puff and push the top sheet pan up as it cooks.               
  5. Place into your oven and bake for at least 35 minutes until golden brown and crispy. I check mine at the 20 minute mark to make sure it’s cooking evenly and if not, I turn my sheet pan 180 degrees to even out the browning. I also prefer my pastry to be a deep golden brown so I cook mine for about 40 minutes and also turn up my oven to 200 degrees celsius fan forced in the last 10-15 minutes of the bake, monitoring closely.
  6. Remove from the oven and gently place the pastry on wire racks to cool completely.                    

Making The Custard

  1. I normally make the custard whilst the pastry is baking, so then both can cool and chill at the same time.
  2. Pour the milk into a pot and gently heat on low. Spilt your vanilla bean pod and scrape out as much of the vanilla bean as possible and add to the milk. Throw in the pod into the milk too and heat on medium until hot and just about to boil. Be careful not to over heat the milk. Remove from the heat.                                                                                                       
  3. Whilst the milk is heating, place the egg yolks into a bowl and whisk to combine. 
  4. Add the caster sugar and corn flour and whisk until creamy and pale.     
  5. Ladle in a small spoonful of milk through a wire strainer into the egg mixture and quickly whisk to combine. Adding a small amount of hot milk at the start tempers the eggs so you avoid curdling and cooking them. Slowly add in the remaining milk over a strainer and whisk to combine.

     

                 
  6. Pour the mixture back into the same pot that your milk was in, making sure there’s no vanilla pod bits still in the pot. 
  7. Heat on medium for 3-5 minutes whilst continuously whisking until the custard thickens and bubbles. You can also use a silicone spatula to scrape the bottom and corners of the pot as those parts are the most prone to burning the custard and creating clumps.
  8. Add the butter and whisk to dissolve and combine. Remove from the heat and continue whisking for another minute to avoid any clumps.
  9. Transfer to a heat proof bowl and allow to cool completely in the fridge. Allow 1-2 hours. It’s ready to use when the custard has thickened even more and is completely cool.

Making the Icing

  1. Place the passionfruit pulp and icing sugar into a bowl and whisk until you get a thick icing consistency. You don’t want it to be too runny as it will run over the edge of the slice and you’ll waste a lot of icing. Set aside until you’re ready to assemble. 

Assembling the Slice

  1. Place one of your pastry sheets on one of your baking sheets with a wire rack on top. This is the base of your vanilla slice. 
  2. Take the custard out of the fridge and give it another whisk to remove any lumps and clumps during cooling. The custard should be thick but smooth.       

        

  3. Using a ladle or spatula, gently place spoonful's of the custard in the centre of the pastry and slowly fill the rest of the sheet, but allowing a few centimetres along the edges of the pastry clear. The custard will slowly creep to the edges as you add more custard and create more height, so keep the edges clear to allow for this. Use a silicone spatula to gently even out and level the custard across the whole pastry sheet.           

     

  4. Carefully place the second pastry sheet on top and gently push down slightly. To make the edges straight and uniform, I use a spatula to gently scrape the custard upwards so it connects and sticks to the top. Sometimes the corners can be gappy and not filled with custard too, so I normally take a small teaspoon and add small dollops of custard to the corners and then use the spatula to even out the custard filling.

     

     
  5. For the topping, if you want to make a traditional vanilla slice, you can simply dust the top with icing sugar. For a passionfruit icing, pour 1/2 of icing into the centre of the pastry top and allow it to slowly flood the top. Use a spatula or butter knife to gently even out the icing. Continue to pour the remaining icing in corners and edges not covered and even out with your whisk, spatula or a butter knife. The icing may run off the edges at some point and that’s perfectly fine. It looks a little more rustic but it’s actually my favourite part to watch.

     

  6. Gently place the slice into your fridge and allow it to fully chill and set overnight. Note, I have tested making the slice two days before serving and having the slice sit in the fridge for over a day to chill and it still works. The more chilling time the better. 

Cutting the Slice

Watch the process:

  1. As I mentioned, don’t cut your slice until it has chilled in your fridge at least overnight and fully set. If it’s not set, you will not be able to cut your slice cleanly.
  2. Find your sharpest and largest serrated knife to cut your slice. I use a serrated bread knife for this.
  3.  Remove the slice from the fridge and gently transfer onto a chopping board.
  4. Gently saw and score through the middle of your slice to cut through the first puff pastry layer.
  5. Once you hit the custard, you should be able to smoothly glide the knife down to the bottom, otherwise you can continue sawing down the custard. Continuous and even pressure is best.
  6. Gently saw and score the bottom of the slice so you cut through the bottom puff pastry layer until you hit your chopping board. Push one of your slice pieces to the side with your knife and you should have a clean cut. 
  7. Make sure to clean/wipe your knife blade every time you make a cut as you’ll have bits of custard and pastry sticking to your blade that will make it harder to make your next clean cut if you don’t.
  8. Repeat several times, cutting each piece in half until you are left with 8 slice pieces or 16 very small pieces. If you are eating this slice over a few days, keep in your fridge and cut as you consume to avoid the custard from drying out. 


Critical Tip & Hacks- Things I’ve learnt about making Vanilla Slice

  • Make and assemble the vanilla slice the day before, cut it the day of serving. Both the puff pastry and custard need to be fully cooled before using/assembling and both need at least 1 hour for cooling. Once assembled the vanilla slice needs to CHILL OVERNIGHT in your fridge to fully set the custard. If you don’t allow this time, when you go to cut your slice, the custard will ooze out and all your hard work will be for nothing, so please allow at least a day prior to make this to allow for chilling time.
  • For the perfectly flat and compressed puff pastry sheets, you need to bake puff pastry between two baking trays lined with baking paper and weighed down in the oven with something heavy on top. I used a cast iron baking dish to weigh mine down.
  • A lot of recipes call for straining the custard before building it into the puff pastry- I find straining custard draining, and after testing this recipe, unnecessary. If you diligently whisk your custard every step of the way and especially at thickening stage, when you’re heating it on the stove and then once it’s cooled you will still get a beautifully silky and smooth custard.
  • A lot of recipes use a square tin as a mould to build the vanilla slice in, but since I don’t have one and one that would fit the dimensions of my puff pastry sheets, I tested whether you could just build it free hand and you can! You just need to make sure your custard has fully chilled and set in the fridge before using and be delicate with the custard when assembling. Make sure to allow a few centimetres around the edges of the pastry sheet as the custard will slowly creep to the edge as you add more custard and push down with the top pastry sheet.
  • It goes without saying to do this anytime you’re cooking, but use the best and freshest ingredients possible. There’s really not much to a vanilla slice in terms of ingredients/components, so there’s really nowhere to hide. You can taste every element, so use the freshest you can get. That means buy:
    • The good puff pastry- I only use Careme puff pastry and that’s what I’ve based my recipe on.
    • Fresh and good quality eggs- I only buy Honest Eggs because of their quality, taste and regenerative farming practices. 
    • Fresh passionfruit- don’t ask me if you can use canned passionfruit or puree because it’s not the same flavour when you make the icing. If you can’t get your hands on fresh passion fruit, just omit the icing and dust your vanilla slice in icing sugar for a traditional vanilla slice.
    • As it’s a vanilla slice, ideally use a vanilla bean pod instead of extract, essence or paste if you can. It makes all the difference in the taste of the custard and after all it is the hero ingredient.

What do I do with all of the leftover egg whites?

 

Vanilla Slice uses lots of egg yolks (10 in this recipe) so you’re going to be left with heaps of egg whites that you’ll need to find a way to use. Some recipe ideas include:

  • Pavlova- obviously if you want something sweet, a pavlova is the easiest way to use up egg whites.
  • Drop it into your soups- For a savoury cold weather option, I like to pour my egg whites into any soup thickened with corn-starch. When you gently swirl the soup with the raw egg in it, it slowly transforms into thin silky ribbons that add extra texture and flavour to your soup. Try my Tomato and Egg Drop Soup or even a drop egg into a Chicken Soup.
  • Granola- If you make granola at home and prefer clumpy clusters, fold in some egg whites into your granola before baking. The egg white will bind the dry ingredients just like sugar/maple syrup does but without any egg taste. It’s a good way to use less sugar/syrup in your granola, if you prefer one that isn’t too sweet.
  • Egg Fried Rice- One of the easiest and comforting ways to use up any eggs. I would mix 1-2 eggs with your whites so you have some yolk and then cook as normal.
  • Bombe Alaska- This dessert has a meringue shell that is perfect to use up your egg whites in.
  • If you love sour cocktails, then use your egg whites for it. The ratio is usually 1 egg white for 1 cocktail, so you could make at least 10 from your leftovers. My favourite sour cocktails are: Passionfruit Sour, Whisky Sour, and Bloody Shiraz Sour Mocktail.
  • I’m not the biggest fan of this, but if all else fails, you could make a simple egg white omelette or scramble. I would just add heaps of herbs, salt and chilli oil to make it as flavourful as possible because I do find an egg white omelette to be quite bland.

 

Watch the process:

How to Make Vanilla Slice

 

How To Cut & Serve Vanilla Slice

 

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