Don’t miss this amazing DIY T-Rex birthday cake tutorial. The step-by-step instructions will make this complex looking cake well within reach!
Editors Note: This t-rex birthday cake tutorial was prepared and submitted by Megan. She participated in Season 12 of the So You Think You’re Crafty challenge. It’s a whole lot longer than my quick crafts and easy recipes, but it’s been so popular I didn’t want to pull it from the site!
T-Rex Birthday Cake Tutorial
Hi everyone, Megan here. Thank you so much for voting to have my project featured as the winning tutorial. This is pretty exciting for me.
Are you all ready for an epic cake tutorial?! Hold onto your hats – this T-Rex cake tutorial is a lot longer post than I thought it would be. Here we go!
What you will need to make this T-Rex birthday cake:
- Dense Cake – see simple recipe at bottom of the post
- Buttercream Frosting
- 2 – Oval Cake Pans
- 2 – Foam Board
- Plastic Wrap
- Cake Leveler – one of my favorite tools!
- Rice Krispie Treats
- Wilton Paste Color
- Cake Decorating Tip
- Green Cake Decorating Dust – this set is the perfect collection of green!
- Edible Shimmer Dust
- Soft Bristled Brush – be sure your brushes are food safe!
- Gum Paste
How to make a T-Rex birthday cake:
Start by baking your denser cakes one day before you plan to decorate in two oval cake pans.
My dense cake starts with a regular cake mix (I used Funfetti) that’s been doctored up a bit. Not only does it hold up better when stacked, but it actually tastes better than a regular old boxed mix.
This recipe will make enough batter to fill two 6-8″ oval cake pans, with a bit remaining. Bake the remainder of the cake in any size/shape pan – you will be crumbling this portion of the cake.
You can grab the recipe for my dense cake at the bottom of this post.
Cool your cakes completely and then wrap them well in plastic wrap. Giving your cake time to settle will make it sturdier.
Create the base for your T-Rex birthday cake:
Using your oval cake as a template for size and scale, trace a light oval shape 1/4 larger than your cake on a piece of white foam core. Add a “snout” to one end of the oval, effectively creating an outline of the final shape your cake will take.
Cut the dinosaur head shape out of your foam core using a knife or sturdy scissors. This will be the base for your cake.
Assembling your T-Rex birthday cake:
It’s time to assemble your cake! The first step is to level your oval cakes. I like to use this leveler, because honestly it’s so hard to get a cake perfectly even with a knife!
Once your cake is level, put some buttercream frosting on your foam base board to hold the cake in place. Place the bottom layer of cake on the board cut side up, smooth side down.
Once the bottom layer is in place, ice the top of the layer. Place the second cake on top of the first, but this time place the cake cut side down, smooth side up!
Once your cake is prepped and ready to go, it’s time to engage your inner creative to round out the back and top of the head and sculpt a dino snout.
The back and top of the head are formed with Rice Krispie Treats.
My Mother had a ton of store bought Rice Krispie Treats on hand and so we used those, but you could totally whip up a batch with your favorite recipe. Simply ensure that the squares you make are nice and squishy so they don’t break down or fall apart while you’re working!
Mash your Rice Krispie Treats together until you have a shape that follows one end of the oval base cake. Attach the Rice Krispie Treats to the cake with buttercream icing.
If you’re having trouble attaching your Rice Krispie “skull” the the cake, a well-placed toothpick can work wonders. Just remember where they’ve been placed if you decide to serve that portion of the cake!
I used more Rice Krispies to make a “dome” shape for the top of the head. This piece of the cake was also attached with frosting.
You could also use Rice Krispie Treats to form the snout of your T-Rex, but I opted to create it out of cake.
Crumble the extra (third) cake baked, as well as the scraps from leveling the cake and mix with a bit of icing. Add your icing in steps. You want your cake to have a thick clay-like texture so that it holds up.
Use your cake clay to knead and sculpt the snout for your dinosaur’s head.
You can see that I used a knife to shave down the oval cake near the snout to give it the right shape.
Using basic kitchen tools or even your fingers, carve out the eye sockets and nostrils on your dinosaur’s head.
Decorate your T-Rex birthday cake:
Cover the whole cake in buttercream frosting. This is your chance to fill in any gaps or irregularities in your Rice Krispie parts. Aim for a fairly smooth finish, but don’t be too worried. This layer will be covered with fondant.
Speaking of fondant, you can either use Wilton’s ready made fondant or you can make your own marshmallow fondant. If you decide to make your own, be sure you err on the side of a stiffer fondant, adding powdered sugar as you go. You want your decorations to hold up!
Pinch off a bit of fondant and roll it in your hands to make a long rope. Use pieces of the rope to make brow bones for over your eye sockets. Pinch the ends creating points in the “bone.”
Set aside a small amount of white fondant.
Make sure to cover the fondant you aren’t using in plastic wrap. You can also coat it (very thin coat) with shortening with your hands before wrapping it, to keep it from drying out.
Color the rest of your fondant green using paste coloring. Knead the fondant over and over to blend the color to your liking. Alternatively, you could purchase ready-made green fondant, but it was a bit to dark for my liking.
It’s time to roll the green fondant that will be covering the entire cake. Make sure your work surface is well-greased with shortening (you can utilize a clean countertop or rolling mat). Roll the fondant until it is large enough to cover the whole cake and hang to the table top, while maintaining at least 3/8″ thickness.
CAREFULLY lift your fondant and place it gently over your cake. Starting at the top, slowly and carefully smooth out the fondant until you’ve worked your way to the bottom of the cake. Make sure you shape it to the curves of your cake, getting it in the nostrils and eye sockets, brows and mouth line. Once you have it smoothed all the way to the edge of the cake, start trimming (with a sharp knife) the excess fondant.
The next step in the process is creating scales and texture on your T-Rex.
I found it easier to raise the cake up for this process so that I could work my texture right to the bottom of the cake. I placed the cake on a sturdy plastic container placed upside down.
I got out a large round shaped cake decorating tip and pushed it gently into the fondant all over – just to make a circular indent that looks like scales. You could leave a bit of the eye sockets with no scales if you like.
Now comes the really fun part. Seriously, I felt like a professional make up artist doing working in more depth and color!
I used a palette of cake decorating dust, borrowed from my Mom. I know a lot of people don’t have something like this on hand. Don’t worry, you can buy individual colors and this set of greens would be PERFECT if you’re replicating this awesome T-Rex birthday cake. I almost wish I would have had it.
Take a soft bristled, food safe brush to add dusting color to your fondant.
I used yellows and greens for the scales. Because most of the greens were brighter, I used a bit of dark brown in and around the eye sockets as well.
I used red dusting powder, along with a charcoal color in the mouth crease.
Tap excess powder onto a paper towel between applications so that you don’t end up with any streaks or large solid patches. As you move on, you can pick up some of the excess powder from the paper towel so that you’re not creating a ton of waste.
I can’t emphasize how helpful it is to remove excess powder from your brush and starting with a light coating of color. You can always add more color in layers, but it’s nearly impossible to remove.
After completing the base colors, I added a little sparkle and luminescence for fun. It just makes the entire cake glow.
This T-Rex birthday cake is really coming together. It’s time to add the finishing touches. Eyes and teeth will make this dinosaur pretty scary!
White fondant, mixed with a bit of gum paste will make for perfect facial accessories. Make sure you knead the two supplies together WELL.
Take two pieces of your fondant/gum paste mix and shape two balls. Flatten the balls just slightly between your fingers – these are your eyes.
I used a small ball tool (fondant tools) to make an indent where I wanted the pupils to be.
I made two tiny balls and colored them dark with some dusting powder. I affixed the dark iris onto the eyeball using edible adhesive.
TO MAKE EDIBLE ADHESIVE: Break up 1/4 tsp gum paste into 1 tbsp water. Mix. Store in a small covered container or jar at room temperature.
It’s time for the teeth! Take some more fondant and roll it into a long, thin rope. Cut the rope into short pieces of varying lengths.
Roll one end of each piece to a point. You can leave pieces straight, or you can curve them a bit -it’s up to you.
Put a dab of your edible adhesive onto the backs of each of the teeth and attach them to the dinosaur’s mouth. You may have to hold the teeth in place for a few seconds to make sure they stick.
Prepare your T-Rex birthday cake for display
The final thing you need to do is put the cake on a board or cake
stand. You can use foam core sheets cut to the size the shape you
You can wrap it in foil, cover it with fondant (use piping gel to stick the fondant to the board), or put ribbon around the edge of the board to hide the raw edge of the foam core.
I went one step further and made fondant letters with fondant molds to spell my son’s name.
I love that this cake is not too scary for my son and his friend, but it’s not cutesy either. The boys loved it – they all fought over who got to eat the eyes and teeth LOL
How to make boxed cake more dense:
Update a Box Cake
- 1 box boxed cake mix (any flavor)
- 1 cup sugar
- 1 cup flour
- 1 pinch salt
- 1 cup milk
- 3 large eggs
- 1 cup sour cream
- Mix boxed cake mix, sugar, flour and salt until combined.
- Whisk milk, eggs and sour cream together until combined.
- Combine wet and dry ingredients and mix until combined.
- Bake at 350° for 30 to 40 minutes (or as directed on the cake mix box).
Thanks so much for sharing Megan and congratulations on your win!
If you make this cake, we’d sure love to see how it turned out. Be sure to email a photo or tag @taunieverett on Instagram.