What’s more perfect for Halloween than a birthday cake that is secretly filled with worms?! So gross and unexpected and perfectly suited for this time of year!

Ingredients for my Worm-filled Birthday Cake
How to Make a Worm-filled Birthday Cake
Make the jello worms.
Combine the jello powder and powdered gelatin in a large bowl. Add the boiling water and stir until dissolved. Place the bowl in the fridge for 20 minutes, or until lukewarm.
In a separate bowl, combine the whipping cream and green food colouring. Add to the jello mixture and mix well.
Extend the flexible straws and insert them into a tall mason jar, flexible ends downward. The straws should fit snugly into the jar. Wrap an elastic band around the straws.
Slowly pour the jelly into the straws. It will pour out into the mason jar as well, but don’t worry! Keep pouring until the mason jar is full. Place the jar into the fridge and leave overnight.
Gently pull the straws out of the mason jar (this may take a little wiggling). Working with one straw at a time, run it under hot water, then squeeze one end and push the worm out onto a plate. Repeat with the remaining straws, then place in the fridge while you assemble the cake.
Make the buttercream.
Beat the butter with an electric mixer until pale and fluffy. Add the vanilla extract and mix until combined. Add the powdered sugar one cup at a time, mixing after each addition. Then beat the buttercream for an additional 3-5 minutes, until light and fluffy.
Dye 1/3 of the buttercream pink and the remaining 2/3 blue. Place the pink buttercream into a piping bag fitted with a large, star-shaped piping tip.
Assemble the cake.
Use a serrated knife to flatten the tops of the chocolate cakes. Use a 3-inch round cookie cutter to cut the center out of 3 of the layers. Save one of the cut out centers.
Place the layer without the center cut out onto your cake stand. Spread some blue buttercream on top in a ring – avoiding the middle. This is so that the worms don’t stick to it!
Layer the remaining cakes on top, spreading buttercream just on the top of the cakes and not onto the inside of the hole.
Fill the hole with the worms. You can toss the worms in a little bit of oreo cookie crumbs to prevent them from sticking to each other.
Don’t add too many cookie crumbs however, because they stick TOO well to the worms and can hide the color and texture of the worms.
Seal the hole in the cake with the reserved circle cake center. If you find that there are too many worms inside the cake to fully push the cake circle into the hole, don’t press the cake in! Simply slice a little off the top of the cake circle so that the top of your cake is flat!
Coat the cake in a thin, even layer of buttercream. This is called a crumb coat and it will trap all of the crumbs within this layer of buttercream and prevent them from showing on the surface. Chill the cake in the fridge for 15 minutes, for the buttercream to slightly stiffen.
Coat the entire cake in a thicker layer of the blue buttercream. Then use the pink buttercream to pipe dollops on the top of the cake, as well as along the base of the cake.
Then slice and disgust all of your guests as worms fall out of the cake!
More Worm Recipes to Try
Worm-filled Birthday Cake
Equipment
Ingredients
1 recipe Chocolate Cake, baked in 4 layers
Worms:
- 2 boxes raspberry jello
- 3 packets powdered gelatin 3 tbsp
- ¾ cup whipping cream 35% fat
- 15 drops liquid green food coloring
- 100 flexible straws
- mason jar
- elastic band
- ¼ cup oreo cookie crumbs
Buttercream:
- 3 cups unsalted butter room temperature
- 3 tsp vanilla extract
- 6 cups powdered sugar
- blue and pink food coloring
Instructions
Make the worms:
- Combine the jello powder and powdered gelatin in a large bowl. Add the boiling water and stir until dissolved. Place the bowl in the fridge for 20 minutes, or until lukewarm.
- In a separate bowl, combine the whipping cream and green food colouring. Add to the jello mixture and mix well.
- Extend the flexible straws and insert them into a tall mason jar, flexible ends downward. The straws should fit snugly into the jar. Wrap an elastic band around the straws, then slowly pour the jelly into the straws. It will pour out into the mason jar as well, but don’t worry! Keep pouring until the mason jar is full. Place the jar into the fridge and leave overnight.
- Gently pull the straws out of the mason jar (this may take a little wiggling). Working with one straw at a time, run it under hot water, then squeeze one end and push the worm out onto a plate. Repeat with the remaining straws, then place in the fridge while you assemble the cake.
Make the buttercream:
- Beat the butter with an electric mixer until pale and fluffy. Add the vanilla extract and mix until combined.
- Add the powdered sugar one cup at a time, mixing after each addition. Then beat the buttercream for an additional 3-5 minutes, until light and fluffy.
- Dye 1/3 of the buttercream pink and the remaining 2/3 blue. Place the pink buttercream into a piping bag fitted with a large, star-shaped piping tip.
Assemble and decorate:
- Use a serrated knife to flatten the tops of the chocolate cakes. Use a 3-inch round cookie cutter to cut the center out of 3 of the layers. Save one of the cut out centers.
- Place the layer without the center cut out onto your cake stand. Spread some blue buttercream on top in a ring – avoiding the middle. This is so that the worms don’t stick to it!
- Layer the remaining cakes on top, spreading buttercream just on the top of the cakes and not onto the inside of the hole.
- Fill the hole with the worms. You can toss the worms in a little bit of oreo cookie crumbs to prevent them from sticking to each other. Don’t add too many cookie crumbs however, because they stick TOO well to the worms and can hide the color and texture of the worms.
- Seal the hole in the cake with the reserved circle cake center. If you find that there are too many worms inside the cake to fully push the cake circle into the hole, don’t press the cake in! Simply slice a little off the top of the cake circle so that the top of your cake is flat!
- Coat the cake in a thin, even layer of buttercream. This is called a crumb coat and it will trap all of the crumbs within this layer of buttercream and prevent them from showing on the surface. Chill the cake in the fridge for 15 minutes, for the buttercream to slightly stiffen.
- Coat the entire cake in a thicker layer of the blue buttercream. Then use the pink buttercream to pipe dollops on the top of the cake, as well as along the base of the cake.
- Then slice and disgust all of your guests as worms fall out of the cake!
