Nanaimo Bars
No-Bake Traybakes

Chocolate Custard Slices

Chocolate Custard Slices. These were a big hit in the Traybakes’ household. They are no-bake. They are easy to make. They freeze well. And they are really rather yummy.

In my exploration of all things baking, I discovered that these Chocolate Custard Slices are incredibly similar to a Canadian traybake called Nanaimo Bars.  The main difference seems to be the inclusion of almonds in the base of the Canadian version.  Although, just like with many Northern Irish traybakes, there do appear to be multiple recipe variations.  But I’m going to stick with calling them Chocolate Custard Slices.

If you aren’t able to get hold of custard powder for the middle layer of this traybake, I’d use a splash of vanilla extract instead.  And by ‘splash’ I obviously mean a measured amount.  This is baking after all, not some throw-it-all-in, fly-by-the-seat-of-your-pants chaos.  I’d use 1 tsp and then use just a little less milk.

But I’ve never had a problem finding custard powder in supermarkets here in the US.  Many have a British/Irish section and it’s usually there, somewhere between the teabags and the baked beans!

Whatever you choose to call this traybake, it has a chocolate-coconut base and rich custardy buttercream topped with a soft chocolate layer.



6oz/170g/1 ¾ cups plain sweet biscuit/cookie crumbs (like Marie, Rich Tea or even Graham Crackers/Digestives)

5oz/150g/1 stick + 2 tbsp butter

2oz/55g/¼ cup sugar

1 tbsp cocoa powder

1 tsp vanilla extract

2oz/55g/½ cup desiccated coconut

1 egg, beaten


2oz/55g/4 tbsp butter

6oz/170g/1½ cups icing sugar (confectioners’ sugar)

2 tbsp custard powder

1-2 tbsp milk


4oz/110g chocolate

2oz/55g/4 tbsp butter


1.  Melt the butter, sugar and cocoa in a small saucepan.  Cool slightly and then quickly beat in the egg and vanilla.

2.  Pour over the crushed biscuits/cookies and coconut.  Mix well and press into a traybake tin.  Leave to cool.

3.  Cream the butter and icing sugar together with the custard powder.  Add milk as needed to create a thick buttercream.  Spread over the base and leave to firm.

4.  Melt the chocolate and butter for the topping in a bowl set over a pan of simmering water.  Spread over the buttercream and when set, cut into squares or slices.  Enjoy!

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    • CJ

      You could always return the pan to the heat for a minute or so just to cook the egg a little. But I totally understand that not everyone is OK with the egg in the base!

  • Stelly

    Thanks. I put it in the oven for 5 mins, just so I could say it was in there – I was worried I’d scramble the egg so let the cocoa mixture cool, then was worried that meant the egg didn’t cook, so figured the oven would make me feel better, lol. Thank you.