Mermaid Number Cake Recipe

Make a splash at your next birthday celebration with this Mermaid Number Cake! Shaped like a special milestone number and adorned with magical mermaid-themed decorations, this cake is the perfect way to celebrate your little one’s big day. Imagine soft, fluffy cake layers sandwiched with creamy frosting, all dressed up with edible seashells, shimmering pearls, and dreamy pastel hues.

Whether you’re making a “5” for a little mermaid fan or a “10” for a double-digit celebration, this cake is a showstopper. And the best part? You can customize the decorations to match your child’s favorite colors.

Why You’ll Love This Recipe

A Show-Stopping Centerpiece

This cake is not just delicious—it’s a work of art. The mermaid theme, combined with the personalized number shape, makes it a unique and unforgettable birthday treat.

Completely Customizable

Choose your kid’s favorite colors, add edible glitter, or mix and match decorations to create a mermaid masterpiece that feels truly special.

Surprisingly Easy to Make

Even if you’re not a pro baker, this cake comes together easily with a simple cut-and-assemble method, making it doable for any home baker.

Ingredients & Substitutions

For the Cake

• 2 ½ cups all-purpose flour
• 2 ½ tsp baking powder
• ½ tsp salt
• 1 cup unsalted butter, softened
• 2 cups granulated sugar
• 4 large eggs
• 1 tbsp vanilla extract
• 1 cup whole milk

For the Buttercream Frosting

• 1 ½ cups unsalted butter, softened
• 5 cups powdered sugar
• 3 tbsp heavy cream or milk
• 1 tbsp vanilla extract
• Food coloring (pastel purples, blues, teals, or pinks)

For the Mermaid Decorations

• Fondant (in pastel colors)
• Edible pearls and sprinkles
• Seashell and starfish fondant molds
• Edible gold or silver dust
• Mermaid tails (store-bought or homemade using a silicone mold)

Step-by-Step Instructions

Bake the Cake

1. Preheat your oven to 350°F (175°C). Grease and line a large rectangular cake pan (or two if needed).
2. In a bowl, whisk together flour, baking powder, and salt. Set aside.
3. In a large mixing bowl, cream together butter and sugar until light and fluffy (about 3 minutes).
4. Add eggs one at a time, mixing well after each addition. Stir in vanilla extract.
5. Alternately add the dry ingredients and milk, beginning and ending with dry ingredients. Mix until just combined.
6. Pour the batter into the prepared pan(s) and smooth the top.
7. Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
8. Let the cakes cool completely before assembling.

Shape the Number Cake

1. Once cooled, carefully remove the cake from the pan.
2. Print or draw the number template of your choice.
3. Place the template on top of the cake and carefully cut out the number shape using a sharp knife.
4. If using two layers, repeat the process for the second cake layer.

Frost the Cake

1. In a large bowl, beat the butter until smooth.
2. Gradually add powdered sugar, mixing well after each addition.
3. Add vanilla extract and heavy cream, then beat until the frosting is fluffy.
4. Divide the frosting into separate bowls and tint each with different pastel colors.
5. Spread a thin layer of frosting on the first cake layer, then place the second layer on top.
6. Apply a crumb coat and let it chill for 15-20 minutes.
7. Pipe decorative swirls, ombré effects, or ocean-inspired designs with the remaining frosting.

Decorate with Mermaid Magic

1. Roll out fondant and use seashell and starfish molds to create decorations.
2. Dust with edible gold or silver powder for a shimmering effect.
3. Add edible pearls, sprinkles, and mermaid tails to bring the theme to life.
4. Arrange decorations along the edges of the number cake for a whimsical touch.

Expert Tips & Tricks

Best Practices

• Use a sharp knife to cut the cake for clean, precise edges.
• Chill the cake layers before frosting to prevent crumbs from mixing into the frosting.
• Experiment with different frosting techniques like ombré or marbled colors for a magical look.

Common Mistakes to Avoid

• Overmixing the batter can lead to a dense cake. Mix until just combined.
• Skipping the crumb coat may cause crumbs to show in the final frosting layer.
• Using too much food coloring can affect the flavor; start with a small amount and adjust as needed.

Time-Saving Tips

• Bake the cake layers a day in advance and store them wrapped in plastic wrap.
• Use store-bought fondant decorations if you’re short on time.
• A piping bag with multiple colors loaded in separate sections can create an effortless ombré effect.

Serving Suggestions

Pairings

Serve this cake with a side of fresh fruit or a scoop of vanilla ice cream for an extra indulgent treat.

Presentation Ideas

Place the cake on a mermaid-themed cake board, and sprinkle crushed graham crackers around the base for a sandy beach effect.

Beverage Pairings

Pair with a refreshing blue raspberry lemonade or a tropical fruit punch to match the ocean vibes.

Storage & Reheating

Leftover Storage

Store leftover cake in an airtight container in the refrigerator for up to 4 days. For longer storage, wrap slices in plastic wrap and freeze for up to 3 months.

Reheating Methods

Let refrigerated cake sit at room temperature for 30 minutes before serving. Frozen slices can be thawed overnight in the fridge.

Frequently Asked Questions

Can I use a box cake mix instead?

Yes! If you’re short on time, a vanilla or funfetti box mix will work perfectly.

How can I make this cake gluten-free?

Swap the all-purpose flour for a gluten-free 1:1 baking blend.

What if I don’t have fondant?

You can use buttercream to pipe seashells and waves instead.

Variations & Customizations

Dietary Adaptations

To make this cake dairy-free, use plant-based butter, milk, and a dairy-free frosting alternative.

Flavor Twists

Try adding coconut extract for a tropical taste or a touch of almond extract for a subtle nutty flavor.

Seasonal/Holiday Versions

For a winter-themed mermaid cake, use icy blue and silver decorations. A summer version can feature bright coral and turquoise hues.

Conclusion

This Mermaid Number Cake is the ultimate birthday showstopper, combining delicious flavors with stunning decorations. Whether you’re making a “3,” “8,” or “16,” this cake will bring magic to any celebration. Have fun with the decorations, personalize it with your child’s favorite colors, and let your creativity shine.

For more beautiful cakes, check out these recipes:
Old-Fashioned Fruit Cake Recipe
Easy Barbie Cake Recipe
Old-Fashioned Southern Tea Cakes

Looking for more baking inspiration? Follow along on Pinterest: Cooking with Callie

Print