Melt Chocolate

Melt your white chocolate candy melts according to your package directions,either in a microwave safe dish in the microwave at 50% power, or low power, or use a double boiler on your stove.

I used plain white on its own for some of the tails. I also make some light pink mermaid tails by adding a touch of pink candy melts into more white candy melts to get the color I wanted.

Pipe Chocolate Into Mermaid Tail Mold

To give my chocolate mermaid tails a dual-tone color, I used edible glitter called luster dust and a brand new paint brush to coat the inside of my candy mold first, before using a plastic bag to pipe the melted chocolate inside.

Use either a piping bag or a disposable plastic bag with the tip cut off to get your melted candy chocolate into the mermaid mold. You can also use a toothpick to help spread chocolate into the edges.

Cool And De-mold Mermaid Tails

Let your chocolate mermaid tails cool completely to room temperature. The smallest point of your chocolate mermaid tails will be the most prone to breaking, so go slow and take your time. Pull the mold away from the candy to release it, then press the thickest spot out slowly.

To avoid breakage, I made my tails thicker in the narrow point of the mold so it overflows a little bit (which looks a bit lumpy on the back-side but no one will see it).

Make your cake batter according to your box cake directions then separate the cake batter into 3-4 smaller bowls to add food coloring. You don’t need a lot of dye to get light or pastel colors. I added half a drop of blue to get a light blue color. I added half a drop of blue and one drop of pink to get the purple colored cake batter. I added one drop of pink to get the pink cake batter.

Grease your pan with butter or oil, then spoon small dollops of each color cake batter into your pan. For a nice colorful mermaid effect, use small spoonfuls to cover the entire pan, then if you have batter left over, add alternating colors on top so every slice has more than one color.

Make your vanilla buttercream frosting with 1 cup of unsalted butter and about 4 cups of icing sugar, 2 tsp of vanilla extract and 2 Tbs of cream or whole milk. Mix the ingredients in a large bowl with a hand mixer or stand mixer until they are completely blended and no sugar crystals remain.

Separate your white frosting into two bowls. Take about ½ a cup of white frosting in a small bowl and add a drop of pink food coloring and half a drop of blue; this should give you a light purple color of frosting.

In the other large bowl of white frosting, add half a drop of blue food coloring. You can always add more but start small and see if you like the shade of blue first. This color will be used to frost your entire cake, so you need more of it.

Scoop out ⅓ cup of the blue frosting and add another half drop of blue food coloring to make it a darker color for decorating with later.

Use your spoon or cake spatula to scoop your mermaid frosting into piping bags. Cut the tip of your piping bag off and put your metal piping tip inside then add your frosting.

For the light purple frosting, use a large open star tip like a Wilton brand #4B tip. For the dark blue, I used tip #96.

To put a large number on a birthday cake like this, use parchment paper or wax paper to create an outline. I used a pen to make a dotted outline until I was happy with the shape, then drew in the lines and cut it out. Use whatever birthday number you'd like, or something different like a heart, initial or mermaid tail shape.

I also used the parchment paper to lay out my mermaid chocolates so I was happy with the look of it before I placed them on my cake. I just took a photo and copied the photo when I was decorating.

First, spread light blue buttercream frosting over the top of your mermaid cake using a cake spatula. It doesn’t need to be smooth; the lines going across look like ocean waves.

Let the blue frosting set for a couple of minutes so it’s less sticky, then place your number made of parchment paper on top of the cake. Use a butter knife to score lightly around the edge of your number to create an outline and remove the paper. Then use light brown sugar to create a thin layer of ‘sand’ inside your number outline. You can also use crushed graham crackers instead of brown sugar if you prefer.

Add swirls and dots of purple and dark blue frosting to your cake with your piping bags and tips. Press down lightly, squeeze out some frosting, then stop squeezing and pull your bag away. Start in alternating corners and create a pattern you like, or make it random.

Keep filling in the edge of your cake with decorations until you’re happy with how it looks.

Add your chocolate mermaid tails (and other seashells if you also have that second candy mold and made them, too).

Then add your finishing touches of frosting and a touch of mermaid themed sprinkles on top of the cake.