The Australian fashion designer showed off her culinary creation on Instagram, which was a Victoria sponge cake covered with vanilla buttercream icing and berries, as well as a pretty purple streak around the outside.
Although the stunning birthday cake looks as though it belongs in a bakery, Storm revealed she was "nervous" about her family tradition after Missy changed her diet.
WATCH: Ronan Keating's daughter Missy celebrates 20th birthday with incredible dinner
"As we said goodbye to the remnants of Missy’s birthday cake last night, I realised I really should share the fantastic GLUTEN FREE recipe I used to make it. Because as many of you know, when the birthdays come around in this family - I bake a cake.
"I always have because that’s what my mum did (as did hers) it’s a family tradition and I remember how much we all used to love her special cakes as kids.
Storm baked her first gluten-free cake for Missy's birthday
"However @missyykeating threw me a curve ball this year as she’s gone #glutenfree so I was tasked with my very first GF cake ever. I was nervous I won’t lie, because I hadn’t had the time to trial any recipes, so spent a good amount of time on Google researching recipes and trying to make a choice based on not much else but the word of whoever was selling it."
She went on to praise Becky Excell's tasty Victoria sponge recipe which she said "turned out a treat!"
Storm continued: "The decorating I freestyled with simple berries and vanilla buttercream icing, with a spruce of silver accent spray and purple food colouring to dress the sides. #reciperecommendation #tastyrecipes #birthdaycake #glutenfreecake #homecooking #glutenfreecooking."
Storm shared a sweet birthday tribute to Missy on Instagram
Missy was clearly delighted with both the taste and the appearance of her homemade birthday cake, commenting: "SO GORGEOUS & SOOO YUMMY. Thank you."
Others were similarly impressed, with one fan remarking: "WOW...that looks awesome!!! I've no doubt it was as delicious as it looks, well done Storm," while a second added: "You are very talented."
A third shared their top tips for gluten-free baking, adding: "Looks gorgeous. I use coconut flour when doing gluten free cakes. It works a treat."