Hannah’s Mermaid Cake for her 3rd birthday party is my first attempt at a decorated layer cake. Decorated with purple and teal fondant mermaid scales, pearl dust, pearl candies and hand piped coral, this key lime pie cake turned out very successful.

Well folks, I bit the bullet and made Hannah’s birthday cake all by myself. I don’t mean to brag (I seriously don’t) but it turned out so dang cute. I have always ordered birthday cakes from our favorite bakery but I wanted to give it a go this year and I’m so glad I did. It was quite a long process but I so loved the end result.

This post will be a tutorial of sorts but as you can guess, I am not an expert by any means in the field of cake decorating so I can’t promise how helpful it will be. Also, the photos I have of the process were taken on my iPhone, oops. I wasn’t sure how it was going to turn out so I figured I would just share a photo of the final product in a post about her birthday. But since it turned out so cute, I decided to dedicate an entire post to the cake.

I also want to let you know that this is not my original design. I searched Pinterest for mermaid themed cakes and came across this one. I loved that it wasn’t too in your face and seemed like something I could manage (with a lot of time). I changed and added a few minor things but the idea is nowhere near mine. Now that my little disclosure is out of the way, on to the cake.

I started with the key lime pie cake, key lime curd filling and key lime cream cheese frosting from Grandbaby Cakes cookbook. If you love graham crackers you have to try this cake. The cake batter has graham cracker crumbs in it making it extra sweet, rich and dense while cake flour helps make sure it isn’t too heavy. The lime curd brings a nice tartness to the sweet cream cheese frosting. The recipe is pretty magical.

I made the cake almost a week ahead of time and wrapped it well in plastic wrap then foil and froze it until the day I decorated it. The lime curd and fondant were made the night before to save on time. If you choose to make the cake and freeze the cake, you don’t have to thaw it before decorating. Just simply trim, layer it with the key lime curd and frost it with the cream cheese frosting.

When it comes to the filling and frosting I have a few tips I’d like to share that will be very helpful if you are new to layer cakes and decorating. First, when filling a cake with curds, jams or other runny fillings it’s important to first pipe the outermost edge of the cake with frosting so that when you place the next layer on top, it doesn’t all drip down the sides. Maybe that happened to me before. Anyway, I didn’t take a photo of that so check out the process here (step 5) if you are a visual person.

Crumb coating a layer cake is important to get a smooth and perfectly iced cake. I don’t think it’s super important when a cake it being covered in fondant but I did it anyway because it made me feel like a professional. Once the cake was crumb coated I gave it another dose of key lime cream cheese frosting and put it back in the fridge while I worked on the fondant.

The fondant, oh the fondant. I made it homemade because then it actually tastes good and it’s not too hard of a process. Making just the fondant is probably about a 15 minute process then a few more minutes per color. It’s all done by hand so you get a nice little arm workout too. It can be made ahead of time (up to a week) and stored in the refrigerator. Pull it out of the fridge an hour before you are ready to use it or microwave it in 15 second increments until it become pliable. While making the fondant isn’t too time consuming, rolling it out and cutting it takes quite some time. Well, I’m sure if you’re an expert or have the appropriate tools it wouldn’t be too bad but it took hours for this first timer using whatever I had to make it work.

When I did the cake trial run, I simply rolled out the fondant with a rolling pin but I couldn’t get it thin enough and of consistent thickness between all the colors. Then the lightbulb went off and I remembered my pasta roller attachment for my mixer. Best. Idea. Ever. It took more time but it was perfect and precise making everything right in the world.

Then I used the wide end of a large piping tip to cut out the circles while the fondant was on my countertop which was sprinkled with cornstarch to prevent sticking. Also not a professional move but it was the right size and meant I didn’t need to go buy a fancy tool I might not use again.

Once ALL the circles were cut out hours later (keep them covered with a kitchen towel in the meantime) the placement could begin.

I randomly chose colors and lined them up along the bottom of the cake.

Then start the next layer, slightly overlapping the first row making sure you place them like you would bricks. Does that make sense? Don’t line them up with the circles of the first row but where the two meet. I’m probably still not making sense so refer to the pictures.

Once all the fondant was on the sides, I started on the top. Again, overlap them slightly with the last row on the sides then gently push them down so that the frosting under the fondant doesn’t show. Continue layering the top until it’s covered.

Next I used some shimmery white pearl candies along the bottom to add visual interest and help hide the frosting peeking out from under the fondant. Then, my favorite finishing touch, pearl dust. I brushed it on lightly with a pastry brush (another case of not quite the correct tool but it did the trick) for the perfect shimmering mermaid effect.

Lastly, I melted some red candy melts in the microwave in 30 second increments then pour it into a ziplock bag, snipped a corner and piped it into natural coral shapes on parchment paper. Once it dried I dusted it with pearl dust and carefully stuck it on the top of the cake.

I had to put a slit into some of the fondant circles and gently push it into the cake.

Then you’re done my friends. I really wanted to make the fork for on top too but by the time I got to this point I was happy with how it looked and didn’t feel like touching fondant for a good while. Instead, I used my silver, antique-esque cake stand to mimic the trinket-y feel of The Little Mermaid’s treasures.

I hope you have enjoyed this amateur cake decorating tutorial for Hannah’s Mermaid Cake. I’ve always been super impressed by cake decorators but I have a new, mad respect for them now and completely understand why cakes are so expensive.