Homemade Lego Birthday Cake

We have recently celebrated our son’s 4th birthday and this went down a real treat!

You can use any cake design you’d like, you can leave it as a simple rectangular or circle shape or you can be more creative and do something like this. To create this numbered cake, I used 4 foil containers and split the batter equally. Once coloured and baked, I split the sponge in half and placed one of each colour on top of each other with some frosting in  between to create a two colour effect. Then I cut the sponge accordingly to create a number 4. It was then decorated with ready to roll white icing, a printed lego edible wafer paper and some edible sugar paste lego blocks.

Check out the full recipe below 👇 IMG_3194

Ingredients for Sponge Cake

  • 350g self raising flour, sifted
  • 3tsp baking powder, sifted
  • 350g unsalted butter, at room temperature
  • 350g light brown sugar
  • 6 large eggs
  • 1 tbsp vanilla extract
  • 40ml milk

Ingredients for Frosting – do this a day in advance and store in fridge overnight

  • 100g butter, softened
  • 250g cream cheese, at room temperature
  • 600g icing sugar, sifted

Ingredients for Piping Gel – do this a day in advance and store in fridge overnight

  • 68g sugar
  • 1 tbsp cornflour
  • 57g lemon juice
  • 59g water

Piping Gel is used to glue wafer paper to the cake tray, or to the cake’s frosting.


  • 4 foil containers 8″x 5″
  • Large mixing bowl for cake batter
  • Small mixing bowl for frosting
  • Saucepan
  • Wooden spoon
  • Spoon
  • Cooling wire rack
  • Small bowl
  • Glass jar/porcelain bowl


  • Muslin cloth
  • Cling film
  • Cake board 12″
  • Your chosen decorations

Method for Sponge Cake

  1. Pre-heat oven on gas mark 4.
  2. Brush 4 foil containers with melted butter (I used 8″ x 5″ rectangular containers).
  3. Add butter and sugar to a large bowl. Use a wooden spoon to cream butter and sugar until combined well and are light and fluffy.IMG_3201
  4. Add eggs one at a time followed by some flour and mix well before adding remaining flour, baking powder and vanilla extract.
  5. Divide mix into the 4 containers and add a tip of your chosen colour. Mix well until colour is evened out in all batter.
  6. Tap the batter with the back of a spoon so it is spread out evenly.IMG_3112
  7. Place in oven and leave for about 25 minutes or until a toothpick comes out clean when you prick the centre. Make sure you rotate and move containers from one oven shelve to the other whilst baking to prevent having a dome shape.
  8. When ready, leave to cool completely, wrap up in cling film and freeze for 1 hr. This will make it easier when applying frosting.
  9. Take out from freezer and leave to tow for about 1 hr before decorating.IMG_3200


Method for Frosting

If the cream cheese is watery,  you HAVE TO drain it. This is a very important step because otherwise the frosting will not come nice and thick! To do this, place cream cheese on a muslin cloth and squeeze gently until most of the water has come out. Set the ball down on a kitchen towel to dry further.

  1. Heat 100g of butter in a saucepan until it becomes incredibly soft but not completely melted. Whisk it until there is only smooth liquid butter.
  2. Unrap muslin and scoop cream into the butter mixture. Whisk the two together until completely mixed. Now switch to a wooden spoon.
  3. Add in icing sugar, little by little (around 150g each time) and fold in very gently.
  4. Place in fridge and leave overnight for a better consistency. Then on the day you are decorating the cake, remove from fridge and leave it at room temperature before applying to cake.IMG_3198


Method for Piping Gel

  1. In a small bowl, dissolve corn flour in half of the water.
  2. Place sugar and remaining water in a saucepan and put on low heat, stir until sugar has dissolved. Add lemon juice and corn flour mixture. Stir until thick and opaque. Cornflour should cook until it becomes opaque.
  3. Switch off flame, leave to cool and store in a glass jar or porcelain bowl in fridge overnight.IMG_3113


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