The Vanilla Slice, also known more commonly as the custard square or the “snot block” is a tuck shop classic here in good old New Zealand. A conversation with a workmate the other day revealled that her mum used to substitute the traditional puff pastry with Huntley and Palmers cream crackers. The luck coincidence of my having to partially cater a morning tea, and this being a recipe in the Cooking Class Cookbook meant I had the opportunity to share this wonderful recipe with you, dear readers.

With a delicious filling of rich vanilla custard, these are the most popular of all slices. The slices are made with packaged puff pastry and topped with passionfruit-flavoured icing.

Actually… I didn’t have and passionfruit. Also, these were indeed extremely popular, with some people coming back for a second slice. Unfortunately though the recipe is made with a boatload of starches, so half the floor had to go out for a walk at lunch to wake themselves up! I was therefore responsible for a marked decline in productivity…

For the slice you will need:

  • 1 packet of Huntley and Palmers cream crackers
  • 1 cup sugar
  • 1/4 cup cornflour
  • 1/2 cup custard powder
  • 1 litre milk
  • 60g butter
  • 2 egg yolks
  • 2 teaspoons vanilla

For the icing you’ll need:

  • 1 cup icing sugar
  • 1 teaspoon butter
  • 1 tablespoon of jam, or, a passionfruit
  • 1 tsp of water

This is a straightforward recipe, with the only real trick being the mixing of the custard – it needs to be as stiff as possible to stop the squares from schmooshing everywhere when you try to eat it.

As you can see in the picture above I’ve lined a 30cm square tin with tinfoil. You can set this aside for a minute while the custard is being made.

The first thing is to put all the required dry ingredients into a suitable pot. It will have to hold at least a litre of liquid.

So these things are custard powder,


corn flour, and sugar. I thought of adding pictures of me doing this, but, well, if you’ve never seen someone pouring different white powders into a pot? You need to live a little.

Mix these three white things well, then add about a cup of the milk and stir it until it combines.

The idea of doing it this way is that only adding a little milk will prevent lumps.

The powders and milk should form a paste that if stirred well, will break up any dried clumps. Really work your wrist and elbow to break it all up, then turn the heat onto medium, add the butter, and add the rest of the milk. DO NOT STOP STIRRING.

OK, the truth is that you can stop stirring for short periods of time. The idea is to stir the custard until it begins to boil, at which point you turn it to a low heat and continue to reduce and stir until it really thickens up. You want it to be able to stand like a solid block at slightly below room temperature.

As you can see above, the mixture is coming along well. So at this point I line the tray with my cream crackers.

And also separated the eggs.

If you’ve not separated eggs before the most simple way is to gently crack your shell, then tip the yolk towards one half of the shell, then tip it into the other half of the shell. With some recipes you need to be really really careful about keeping yolk and white separated (meringues for example), but with this it’s not too much of a worry.

Right. So back to the stirring. This took blimmin ages. But, I got there in the end, and the custard was very thick.

Next stir in the vanilla (you can use essence, but I quite like this paste from the supermarket), and the egg yolks. Mix thoroughly.

Once mixed, spread the custard into the pre-prepared tin! Easy.

Once the custard is in, immediately place another layer of cream crackers on top and press them firmly into the slice.

At this point you can put the slice to one side, and make the icing. This is pretty easy stuff.

Sift the icing sugar into a bowl, melt the butter in the microwave, then add the butter and water.

As I said earlier, I didn’t have any passionfruit, so I used some berry jam instead. Mix the lot until you have a consistency about right for spreading over the slice. If it’s too dry, add a tiny bit more water. Too wet and not dramas, just add a little more sugar.

Then, spread the icing evenly across the slice.

Once it’s iced, pop it in the fridge to set properly.

In the morning you can cut it into slices, and voila! Custard squares. Try not to eat too many. Especially not at breakfast.