Vanilla Custard Slice Recipe

These vegan custard slices are a dreamy combination of smooth vanilla custard layered between crisp, flaky pastry and topped with a pretty, feathered vanilla icing.

Custard Slices are one of Mr Cakes favourite desserts from our pre-vegan days and you can never seem to find any vegan ones around where we live. They're also much easier to make than they look, the hardest part is waiting until they are fully set before attempting to cut them! You simply bake your puff pastry and whisk up a saucepan full of my creamy vanilla custard, before layering everything together. I finished mine with a thin layer of hot water icing to make a fancy feathered pattern, but you often find them simply dusted with a little icing sugar in bakeries as well.

This recipe makes six giant slices or more smaller. They are best eaten within a few days of baking and need to be stored in the fridge.

Makes six large slices or more smaller

For the custard layer;

135g caster or granulated sugar

45g vegan butter

1 tsp vanilla powder

700g plant milk + 80g plant milk

80g cornflour

1 sheet of vegan puff pastry

For the icing topping;

200g icing sugar + 4tbs boiling water

30g icing sugar, 1 tsp cocoa powder, 1 tbs boiling water

You will also need; two large baking trays, saucepan, fork, whisk, spoon, serrated knife, two small bowls, cocktail stick, 7" x 11" baking tin or similar size, piping bag - optional

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How to make your cakes;

1. Pre heat the oven to 200°c

2. Unroll your puff pastry and use a fork to prick small holes all over the sheet. This will stop the pastry puffing up too much in the oven

3. Bake for 8-10 minutes, then remove from the oven and firmly press down using another baking tray to flatten the pastry

4. Return to the oven for another 8-10 minutes until the pastry is looking lightly golden

5. Remove from the oven and press down firmly again with the base of a baking tray to flatten the pastry

6. Set aside to cool

7. Move on to making your custard. In the saucepan add the sugar, butter, vanilla and 700g plant milk. Heat on a low to medium heat until everything is melted together. You do not want the custard to boil!

8. In a small bowl, mix together the cornflour and 80g plant milk to make a thick paste

9. Once everything in the saucepan has melted together, very slowly add the cornflour mixture while continuously whisking

10. Keep whisking until the custard has thicken. The texture should be thicker than if you were making a regular custard to pour on top of a cake. Do not stop whisking, as this is when you can end up with lumpy custard

11. Once the custard is ready, cover the top with clingfilm by pressing the clingfilm on to the top of the custard. This will help prevent a skin from forming

12. Once the pastry is full cool you can begin to assemble. If the custard is still slightly warm that is ok, but it shouldn't be piping hot

13. Line your baking tin with baking paper. Make sure the paper edges are slightly higher than the sides to make it easier to lift out the custard slice once it is set

14. Carefully cut your pastry down the middle to make two even rectangles. My pastry fitted perfectly across my usual 7" x 11" baking tin. It was a little short, but is just folded my baking paper up to meet the pastry

15. Place the first half of pastry into the bottom of the lined baking tin. You want the smooth side down and the fork pricked side up

16. Remove the clingfilm from the custard and give it a good whip with the whisk or a large spoon to bring it back to a smooth consistency

17. Spoon the custard over the bottom sheet of pastry and evenly smooth it out

18. Place the second sheet of pastry on top of the custard and lightly press down to stick everything together. You want the fork pricked side down, so that the smooth side is on top. Set aside

19. Mix up your hot water icing. Add the icing sugar and boiling water to a small bowl and mix together to make a smooth, thick but spreadable white icing

20. In the second small bowl add together the icing sugar, cocoa powder and boiling water and mix to form a chocolate smooth, thick but spreadable icing

21. Pour the white icing over the top of the pastry and gently nudge it to the sides to make a smooth, even layer

22. Add the chocolate icing to a small piping bag or use a spoon to make thin lines going across the white icing

23. Immediately use a cocktail stick or thin knife and drag it gently up and down the pastry, this should feather the white and chocolate icings together to make a pattern. You need to do this straight away as the hot water icing sets quite quickly

24. Place the baking tin of custard slice into the fridge for at least two hours or even overnight until the whole thing is completely cold and set

25. Very carefully portion up your custard slice. You want to use a serrated knife and make a gentle sawing motion. If you press down to firmly with a blunt knife it will snap the pastry and the custard will just splurge out the sides. I was a little scared of squashing the whole thing, so I cut mine still inside the tin, but actually as long as you are gently sawing you will be absolutely fine removing the custard slice from the tin first and then cutting it up!

26. Now your custard slices are ready to eat!

Tips & Tricks!

• Most brands of ready made puff pastry and vegan friendly but do check the label

• If you don't fancy making the hot water icing, you can just dust the tops with a little icing sugar

• The key thing is to make sure that everything is fully cold and set before attempting to cut it up. When you do slice it up, use a serrated knife and a gentle sawing motion rather than pressing down

• This is my cake tin - my tin is 7" x 11" x 2" - https://amzn.to/45YU9Do

• These are my mixing bowls - https://amzn.to/489iB6s

• This is my small angled palette knife - https://amzn.to/3VLIO3w or this one is slightly cheaper https://amzn.to/46j4VTY

• I always use this vanilla powder https://amzn.to/46GsRSC