Recipe: Tim Tam Cake

Mother’s Day Celebration

God bless our mums - love you!

A few weeks ago a Tim Tam tree magically sprouted near my work at Martin Place, offering glistening Tim Tams ready for harvest. A clever marketing ploy offering free Tim Tams, I was an easy target. I was giddy with glee roaming the Tim Tam forest, stuffing my pockets with these iconic chocolate biscuits… ok so I went a bit nuts, procuring no less than 40 Tim tams.

The Tim Tam tree! (photography courtesy of my workmate Linh - she gots skillz)

I stashed most of my pickings at work “in case of emergencies”, for those certain days that can only be endured with a chocolate fix. I especially love having Tim Tams with my coffee, where I make Tim Tam Bombs. I bite off both ends of the Tim Tam and use the remains as a straw to suck up the hot coffee. As the biscuit softens and the chocolate begins to melt, I quickly have to gobble up the coffee-soaked chocolaty goo. Yum.

There was limited space in my secret stash, so with the “extras” I decided to make a Tim Tam cake for Mother’s Day, a special cake for the special women in my life – my dearest Mum and Mum-in-law.

Happy Mother's Day, Mums! My Mum on the left, and my Mum-in-law on the right

Mum loves her coffee as much as I do. Though I’m not sure if she knows about the Tim Tam bomb, at least she can enjoy the perfect cake with her coffee, as she finally gets to play the next instalment of COD.

Mum enjoying Mother's Day

The week before Mother’s Day, disaster almost struck as I became terribly sick. I was trapped at home, forced to do nothing but rest. So after a painfully slow recovery I was finally feeling much better by the weekend (having a few Tim Tam bombs sure helped). It was a welcome relief to return to the kitchen, and nothing was going to stop me from my Mother’s day preparations.

I love you Tim Tam cake

The beauty of this cake is that it looks so impressive for such relatively little effort. There are three stages to making it – firstly making the chocolate sponge cake, then filling it with chocolate butter cream and crushed Tim Tams, and finally covering it all with chocolate ganache (no decorative piping involved!). I found the hardest part was crushing the Tim Tams. Wielding my trusty rolling pin, my first blow at the distinctive brown packet seemed so counter-intuitive, I remember feeling strangely emotional as I heard the first crunch. But I managed to persevere, and as I repeatedly whacked away the bashing soon became quite therapeutic, and the biscuits quickly turned to Tim Tam rubble.

First bite of the Tim Tam

I left the job of icing to the very last minute. After centering the cake, I protected the serving platter from chocolate drips by sliding a strip of baking paper under each edge of the cake. After pouring the chocolate ganache all over the cake, I popped it in the fridge to allow the chocolate to set slightly. I then pulled off the chocolate-catching strips just before serving and voila! A Happy Mother’s Day indeed!

The cross section of the Tim Tam cake

Recipe: Tim Tam Cake

Based on Raspberri Cupcake’s recipe
For the chocolate sponge cake
Gives a light, fluffy cake, with a delicate chocolate flavor. Not too sweet, it provides enough structure to support heavier, butter-based icing.
You need two 17x27cm rectangular baking trays, but improvise if you don’t have this – utilise a larger baking tray and cut the cold cake in half, into two equally sized rectangular cakes.


  • 4 large eggs
  • 110g caster sugar
  • 65g corn flour (cornstarch)
  • 35g Dutch-process cocoa (I used Cadbury Bourneville cocoa, and it turned out great)
  • 1 tbsp plain flour
  • 1 tsp cream of tartar
  • ½ tsp bicarbonate of soda
  • 50g unsalted butter, melted and cooled


  1. Preheat oven to 180°C. Grease two 17x27cm rectangular slice/brownie tins (or one larger sheet cake tin) with melted butter, then line with non-stick baking paper.
  2. Whisk eggs and sugar in an electric mixer until thick and pale (5-6 minutes, it should triple in volume).
  3. In 3 batches, sift over corn flour, cocoa, flour, cream of tartar and bi-carb soda. Fold in the dry ingredients with spatula after each addition.
  4. Fold in butter, then spoon into prepared tin(s). Bake in centre of oven until cake springs back when lightly pressed (10-12 minutes). Turn onto baking paper covered wire rack and cool completely. If you baked one large cake, cut into two equal sized rectangular cakes once the cake is completely cold.

Chocolate buttercream filling
The following recipe has much less icing sugar than what Rasberri Cupcake’s recipe originally had, as I’m not a big fan of sugary icing. It turned out deliciously thick and chocolaty, but not sickly sweet, so I was quite happy with how it turned out.

Step 3 of icing the cake

  • Ingredients
  • 100g butter, removed from the fridge 30 minutes before starting
  • 150g milk chocolate, melted and cooled to almost room temperature
  • 1 cup icing sugar, sifted
  • 1 tablespoon milk (optional)
  • 1 packet of Tim Tam biscuits, crushed


    1. Beat butter light and fluffy. Add sifted icing sugar, 1 tablespoon at a time and beat well after each addition. Once all the icing sugar has been added, continue to beat until smooth and pale.
    2. With a rubber spatula, add melted chocolate and fold through until mixed thoroughly. It will be quite thick at this stage, so if you’d like it a little thinner, slowly add milk to get the icing to the texture you want. I didn’t add any milk and it was gloriously thick.
    3. Spread icing over the top of one of the cakes, and then top with the crushed Tim Tam biscuits. Sandwich the other cake on top of the icing and biscuits.
  • For the chocolate ganache topping

    Pouring over the chocolate ganache


    • 300ml pouring cream (35% milk fat pure cream – I used thickened cream, because the grocery store ran out, and it worked perfectly)
    • 400g milk chocolate


    1. Break up chocolate into small pieces and place in a large mixing bowl. Slowly heat cream in a small saucepan. Just as it starts to come to the boil, remove from the heat and cool for a couple minutes.
    2. Pour hot cream over chocolate and set aside 10 minutes to allow chocolate to melt. Mix cream and chocolate together until smooth using a whisk, then cool until it reaches room temperature and thickens.
    3. Lay down some baking paper to catch the drips, the pour the ganache over the top of the cake, using a spatula to ensure the ganache covers all the top and sides of the cake. Chill in the fridge until the ganache sets, then peel off the bottom baking paper and serve cake at room temperature. Use a big cookie cutter or large spoon to cut a cheeky ‘bite’ out of the cake just before serving.


    Oli taking one for the team - chocolate should never go to waste

    Steph just had all 4 of her wisdom teeth out so was having soft foods. Like leftover chocolate ganache. Hmmmm...

    To all the Mum's out there, Happy Mother's Day!

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13 thoughts on “Recipe: Tim Tam Cake

  1. Mmm what a great way to celebrate Mother’s Day! Your chocolate sponge looks fantastic :) Haha I love the idea of smashing Tim Tams as a form of stress therapy! And then eating them, of course.

    • I wouldn’t have been able to do it without your recipe, so thank you Steph!
      Everyone loved it, not just the novelty of eating a giant Tim Tam, but it was a really yummy chocolate cake. We have a winner!

  2. This cake is amazing! Thanks for saving a slice for G and I! The ganache was especially awesome. The whole cake was moist & lovely. Teehee! tim tam tree! I wanna grow one in our backyard.

    • Haha yeah she’s pretty special ;)
      I really liked this as a chocolate cake – wasn’t too chocolatey that I went cross eyed, but sure was chocolate heaven in a mouthful!

  3. A superb Tim Tam Cake truly made our day a memorable one. Wish I could eat more and keep some for myself only..he .he. Love it..Highly commendable!!!

  4. Pingback: Strawberry Tart with Creme Anglaise | Epicuriously

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