Treasure Chest Birthday Cake

Treasure Chest Cake with text


It was Cathal’s 4th birthday last week. He’s my middle child and every year he likes to test my birthday party planning by throwing a spanner in the works. Last year he insisted on a shop-bought Peppa Pig Cake from Tesco rather than one of the homemade delights that are my labour of love. The birthday rules in our house say that the birthday child suggests the theme for their party and their cake, so I bought the Peppa cake. Cathal this year chose to test me on one and give me a break on the other. He chose a treasure chest birthday cake (seriously!), then added that the lid would have to be open (eek) but insisted that he didn’t want his party at home. Clever kid looking after his mama like that. So while I celebrated not having to tidy before, during and after the party I put off even thinking about how I’d make the cake until the morning I had to make it. Then, I went and bought the ingredients, and only after the cake itself was made did I even consider how on earth I would make a treasure chest with an open lid from cake. I stood in my kitchen, surrounded by cooled cake with a knife in my hand looking puzzled at 9pm on a Saturday night. My husband left the room to allow my, um, “art” to happen. And it did, eventually, see.


Helping soften the butter

Cathal insisted he would help make his cake, so I gave him and knife and a block of butter straight from the fridge and let him “soften” it by chopping it into small cubes before I creamed it with the sugar to make the cake.

I made the Rachel Allen Chocolate Letter and Number Cake again as it was such a big hit before and sculpts well. You can check out the recipe here, I made TWO of them (yep, 12 eggs worth) as I wasn’t sure yet how I’d make the cake. I now realise that it was too much cake ( I cannot believe that I typed those words). The double recipe filled my roasting tin, a 2lb loaf tin and a big square brownie tin too. I also made a double quantity of Chocolate Buttercream.

To decorate you will need:
1 very long yellow licorice lace
3 packets of smarties
1 packet chocolate fingers
4 X 4 finger Kit Kats
€1 worth of Haribo Rings from the sweetshop pick and mix
Chocolate coins – these are much harder to find than you think unless it’s around Christmas or Easter. I ordered mine on Amazon and found silver ones in a euroshop.
2 Candy watches (necklaces would be good too)
2 Euroshop necklaces (I got mine in a party favours section)
We also had some Jake and the Neverland Pirates cake decorations that we got in Woodies’ party section

How I turned a lot of cake into a treasure chest:

When the cake was cool I stared at it for a while waiting for inspiration. It was around this time that my husband left the room. I ate some smarties and then the inspiration came.

I cut the roasting tin cake in half and placed the two pieces on top of each other, with chocolate buttercream in between them.

Next I took the loaf tin cake and cut it in half horizontally. I cut the bottom half those in half again lengthways.

I used the top bit as the lid, and bits cut off the other parts to prop it open. I had a mini disaster as my lid broke in half as I was trying to figure out how to prop it up but luckily buttercream is a great hider of mistakes.


So, I turned the cake side view on and decided where I wanted the lid to open, at what angle. Then I put one of the long thin strips behind the lid, and I trimmed the other long thin strip, cut it in 3 and wedged the lid open underneath with 2 of the parts. the 3rd I saved, just in case.

When I’d figured out what fitted, I covered everything in sight in chocolate buttercream, dipping the knife in hot water to keep it smooth between applications. Don’t worry about getting a smooth edge as everything is going to get covered in sweeties anyway.




Assembly side view


When it was all covered in buttercream I stuck chocolate fingers on to the front part and Kit Kat fingers from the sides all around the back as they are taller.




Then I cut the long yellow licorice lace in four and put it over the hump of the lid. Next I filled that area in with smarties in no particular colour order. Finally, I added the treasure – the Haribo rings, chocolate coins, necklaces and watches, more smarties. Finally the Jake decorations and the candles were added. I brought extra sweets to the playcentre where we had the party as I knew that kids would be looking for then, and I wasn’t wrong.

The cake went down really well, Cathal was thrilled and many kids said “wow” when they saw it. Like most of the cakes I make it wasn’t complicated and requires very little skill, just lots of buttercream and sweets to cover the messes.

It’s slightly tricky to cut and the back slices are the size of a sliced pan. Luckily, any kids nearby will “help” the cutting process by grabbing all the sweeties that get in your way.

Let me know if you try it.






The finished product




  1. Too much cake, eh? I don’t believe that for a second 😉 The finished product looks amazing. And super delicious! Lucky boy!

  2. Wow! That looks amazing and delicious too. I think you’re so brave to make a cake just like that without plans etc.. I made a butterfly one year, but it was just flat – like 2 capital Bs back to back.. We have birthdays coming up but I’m not sure if I’m brave enough to do this. I also need 2 cakes as my twins insist on their own cakes and rightly so! 😉

  3. I still don’t know how you did it but it looks fantastic! I thought my kids gave me some tough challenges but now I see I get off lightly!

  4. When ever I see wonderful cakes like this (and this one is actually amazing) I sigh. My kids and the gang I had in the house never got such pleasure. We (my friend and I) used to get the huge family block of ice cream and cover it with every sort of sweet imaginable. Then we would put the candles on.
    Except for the few birthdays when we lost/forgot to buy the candles, and we used night lights.
    I will show my gang your fab cake tomorrow and I can just imagine the comments!

  5. And I thought I did well when I actually baked a birthday cake for my 3 years old ( I usually buy a Tesco one, I’m a terrible cook). That cake just looks amazing !!!

  6. I’m making a treasure chest cake for my grandsons 3rd birthday in a couple of weeks. This looks brilliant and thanks for the instructions on how to put the lid on. That bit was worrying me.

  7. Beautiful cake.

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