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Cool 6th Birthday Mermaid Beach Cake

I made this mermaid beach cake for a 6th birthday celebration.

Cake Ingredients

  • For chocolate cake:
  • 2 cups all-purpose flour
  • 2 cups sugar ¾ cup unsweetened cocoa powder
  • 2 teaspoons baking powder
  • 1½ teaspoons baking soda
  • 1 teaspoon salt
  • 1 cup milk
  • ½ cup vegetable oil
  • 2 eggs
  • 2 teaspoons vanilla extract
  • 1 cup boiling water

I started by making the cake. I doubled this recipe because I was using a 9×13 width (inches) and 3 inch length square cake tin. I added all of the dry ingredients, such as the flour, baking soda, baking powder, salt and sugar. I mixed these until combined. I added the milk, vegetable oil, eggs and vanilla extract together until well combined, and then I added the boiling water gradually. Afterwards it was beaten on high speed to add air to the batter for about one minute, though if beaten too long could result in large bubbles in the cake. Since I have a particularly strong oven I do not preheat. If I were to preheat my food would burn a lot quicker.

Icing Sugar

  • 1 cup butter (2 sticks or 227g), softened
  • 3 – 4 cups confectioner’s sugar, sifted
  • 2 teaspoons vanilla
  • 2-3 tablespoons milk, heavy cream, or half-and-half
  • Blue food colouring
  • Green food colouring
  • Blue sanding sugar or blue glitter (optional)

I quadrupled this icing recipe for the cake, though I had a little left over. For the icing I got the butter and beat it on high until it was very light and fluffy. Be careful here because if you were to over beat the butter and milk would separate and create buttermilk. Afterwards, add half of the icing sugar and half of the milk. As soon as the icing sugar is combined beat on high for about 10 seconds. Repeat with other half, this time adding the vanilla as well. If icing is not desired consistency leave to refrigerate for 15 minutes or add more milk.


  • Brown sugar (2-3 table spoons)
  • Vanilla wafers  (about a whole box) Or graham crackers.
  • 2 1/2 table spoons of Gold sanding sugar or gold glitter (optional)


  • Haribo turtles (only 2 used)
  • Any small mermaids at your local store (1 used).
  • Multiple sugar decorations (we bought these from our local cooking shop, but you can get most of them online. 

Cake Assembly

To flatten the cake, I cut along where the cake had domed. I frosted the first cake using the uncolored icing, and then cut the second cake and put it on top of the first. Next, I cut the chosen corner down diagonally, moving very slowly and not cutting into the lower layer. Then I iced the sides with uncolored icing, first piping it with a big and long nozzle and then using a spatula to spread it out. My icing was a little stiff so I sat the spatula in hot water every now and then to help the icing spread without the crumbs coming up.

I let that sit for about 30 minutes to an hour in the fridge, which will help the crumbs to not come up when putting on the second (and final) layer.

While that set I made the sand, combining the ingredients and crushing with a mortar and pestle. I then left to refrigerate for however long necessary.

Then I took the icing out and separated it into 3 bowls,

The kids were amazed by the cake, and the parents were even more amazed at how good it looked (especially at my age!)

To make this cake you need a lot of time and patience, and I believe that was the most difficult part. I chose to make this cake because the theme of the party was beach, and though it was for a 6 yr old girl I think this cake can be used for one of any age.