Ghoulish Coconut and Lime Slime Cake

Ghoulish Coconut and Lime Slime Cake

Serve up a treat this Halloween with my recipe for this Ghoulish Coconut and Lime Slime Cake.

A real horror story

The last time I baked this cake, things really didn’t go to plan. For a start…I forgot the limes. And you can’t really make a lime cake without the limes! By this point the cake mix was already in the tins so I left it. At least I had remembered to add in the desiccated coconut.

The cake had been in the oven for about 10 minutes when I realised I’d not just forgotten the limes, I’d also forgotten to colour the sponges green! I swear I’d loose my head if it wasn’t screwed on sometimes.

When the cakes came out of the oven one was so domed that I couldn’t cut it into two even slices (normally the cake would have 4 layers, each of which is roughly 1-1.5 inches tall but I had to settle for just 3 layers this time. Jon at the domed piece I cut off the top! He’s a lucky man…

The good news was that the cake tasted delicious and if you follow the recipe properly you won’t have the same issues I did. Note to self…don’t try and bake a cake when you’re in a rush!

Halloween layer cake: Coconut and Lime Slime Cake. Decorated with black buttercream and green white chocolate ganache drip and coconut meringue ghosts.

Coconut and (s)lime

Presuming you don’t forget to include half the ingredients like I did, each slice of this cake has four layers of moist, tender sponge cake flavoured with desiccated coconut and fresh lime. Between each of those layers is a thin coating of lime curd. I added extra green food colouring to make it look even more like ghoulish slime!

I then sandwiched each of the layers of sponge with buttercream that had been flavoured with lime and coloured as black as the nights sky. Don’t bother trying to turn buttercream black with regular food colouring, you’ll need proper gel food colouring for it to work. I use this Black Gel Icing Colour from Wilton.

Once I covered the cake with the buttercream I put green and black sprinkles around the bottom of the cake. Then mixed up a white chocolate ganache, coloured it green and dripped it down the sides of the cake to make it look like slime!

Finally to decorate I made some coconut meringue ghosts which sat on top of the slime with a little more buttercream and green and black sprinkles. You can get the recipe for the coconut meringue ghosts here.

I also used a “spooky” cake topper from Not On The Highstreet if you want to recreate the whole look!

Halloween layer cake: Coconut and Lime Slime Cake. Decorated with black buttercream and green white chocolate ganache drip and coconut meringue ghosts.

The recipe

This has to be one of my favourite Halloween cakes now. The sponge is so tender and the coconut and lime is a real zip! It went down a treat at our Halloween Cake Club.

Halloween layer cake: Coconut and Lime Slime Cake. Decorated with black buttercream and green white chocolate ganache drip and coconut meringue ghosts.

Coconut and Lime Slime Cake

Emma Walton
This Halloween treat is made with coconut and lime for a fun, slime covered cake. Get the recipe for the coconut and lime slime cake here.
5 from 3 votes
Prep Time 25 mins
Cook Time 35 mins
Decorating Time 45 mins
Total Time 1 hr 45 mins
Course Dessert
Cuisine British
Servings 16 people
Calories 746.89 kcal


For the cake

For the icing

  • 450 grams icing sugar
  • 350 grams butter
  • 2 tbsp coconut cream
  • 1/2 lime juice only

For the filling

For the drip effect

For decoration

  • green and black sprinkles
  • 5 coconut meringue ghosts
  • spooky cake topper


For the cake

  • Pre-heat the oven to gas mark 4 (160 C), and line three 7 inch cake tins with grease proof paper.
  • In a large bowl, whisk together the butter and the sugar until soft.
  • Beat in the eggs one at a time until and beat well until the mix is creamy and pale.
  • Add the zest and juice of the limes and mix until combined.
  • Sift the flour into the bowl along with the desiccated coconut and fold through until the flour is fully incorporated.
  • Pour the cake mix into three separate cake tins and bake for 35 mins until springy to the touch and a skewer comes out clean.
  • Allow to cool in the tins for 10 minutes before turning out on to a cooling rack.

For the decoration

  • Once the cakes have cooled completely, beat together the butter, icing, creamed coconut and lime juice.
  • Add roughly a quarter of a tsp of black food colouring and beat until the colour is throughout – add more food colouring if required.
    Black buttercream icing
  • Using some of the buttercream as “glue” place the bottom cake layer onto a cake board.
  • Mix the lime curd with a little green food colouring to make it a vivid green.
  • Spread half of the coloured lime curd on the sponge, followed by 1-2 tbsp of the black buttercream.
    Lime curd on sponge
  • Stack the next layer on top and repeat with the remaining lime curd and another 1-2 tbsp of the black buttercream.
  • Stack the third and final layer on top.
  • Using an angled spatula, spread a “crumb coat” of black icing around the outside of the cake and on top, trapping any stray crumbs.
  • Put all but 3 tbsp of the remaining buttercream into a piping bag and pip it around the outside of the cake.
  • Again using an angled spatula, carefully smooth the icing until the sides are straight. 
  • On the top of the cake, drag any excess buttercream into the centre of the top of the cake and smooth until level.
  • Using a teaspoon, carefully decorate the base of the cake with green and black sprinkles.
  • Place the cake to chill in the fridge while you melt the white chocolate.
  • Break the white chocolate into cubes and place in a bowl.
  • Pour 2 inches of hot water into a large bowl and rest the bowl of white chocolate on top of the hot water.
  • Stir the white chocolate until completely melted.
  • Take the melted white chocolate off of the heat and add some green food colouring to the white chocolate until it is roughly the same colour as the lime curd.
  • Pour the melted white chocolate into a piping bag and cut a small hole.
  • Carefully pipe around the top edge of the cake allowing it to drip down slightly (try to make the lengths of the drips different for a more natural drip effect.)
  • Cover the rest of the top of the cake with the melted white chocolate.
    Halloween Slime Cake
  • Place the coconut meringue ghosts and the “spooky” cake topper on top of the cake and let the white chocolate set.
  • Put a Wilton #2D (or similar large drop flower tip) into a piping bag and fill with the leftover black buttercream.
  • Pipe the buttercream around the ghosts and cake topper.
  • Top the buttercream with a few more black and green sprinkles to finish.


There are a few tools you’ll find handy when baking this, and many of my other, cakes:
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Calories: 746.89kcalCarbohydrates: 80.51gProtein: 7.35gFat: 42.82gSaturated Fat: 26.52gTrans Fat: 1.34gCholesterol: 163.15mgSodium: 335.24mgPotassium: 132.85mgFiber: 1.35gSugar: 58.2gVitamin A: 1115.55IUVitamin C: 3.95mgCalcium: 58.73mgIron: 0.77mg
Keyword coconut, halloween, lime
Tried this recipe?Let us know how it was!

More Halloween Recipes

Here are some of my favourite ghoulish treats!

You can find the full archive of Halloween recipes here.

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