First up lets make the sponge; preheat your oven to 180°C/160°C fan oven/gas 4. Grease and line 2 x 7inch round cake tins.
Put the butter, oil and sugar in a mixing bowl and beat with a wooden spoon or electric mixer until pale in colour and fluffy in texture.
Add the eggs one a time beating well and scraping down the sides of the bowl after each addition. Then add the Vanilla Extract and Cocoa Powder and mix well.
Squeeze in the Red Gel Food Colour and mix until the colour is evenly mixed through. Sift over the flour and pour in the buttermilk, mix until all incorporated.
In a small bowl mix together the Bicarbonate of Soda and vinegar then add to the cake mixture stirring it in by hand until it is all incorporated.
Divide the mixture evenly between your prepared cake tins then bake in the oven for 35-40 minutes until an inserted skewer comes out clean. Allow the cakes to cool in the tins for 15 minutes then remove from the tins and place on a cooling rack to cool completely.
Whilst your cakes are cooling it’s time to make the jelly; soak the leaves of gelatine in a bowl of cold water for about 5 minutes until softened.
Mix together the cordial and water, add a few drops of green colour gel to create a slimy green colour. Pour into a small saucepan and add the softened gelatine leaves. Heat over a low heat stirring until the gelatine has melted and then remove from the heat.
Line a 6” cake tin with cling film and pour in the jelly mixture until about 2 cm thickness. If you have any rounded ice-cube trays you can use your left over jelly mixture to fill these and create bubbles on top of your cauldron.
Pop the jelly in the fridge and leave to set for a couple of hours.
Your ganache will need some time to thicken so it is a good idea to make it whilst your cakes are cooling as well. Break the Chocolate into pieces and pop into a microwavable bowl with the butter. Melt together in the microwave in 30 second bursts stirring between each burst until you have a lovely smooth mixture.
Pour the cream into the chocolate mixture whilst stirring and continue to mix until all the cream in combined. Squeeze in a tube of black colour gel and mix through the ganache.
Leave your ganache to thicken at room temperature, stirring every now and again.
Once your cakes are cooled and your ganache is a lovely spreadable consistency it’s time to assemble the cake! Use a serrated knife to cut any domed tops off the sponges and pop one sponge layer on cake board. Spread a layer of ganache over the top of the sponge and sandwich your other sponge layer on top.
Cover the top and sides of the cake in a thin coat of ganache to create a crumb coat and smooth out with a palette knife or cake scraper. Pop in the fridge for 30 minutes to allow the ganache to set.
Once set cover the top and sides of the cake in another layer of ganache and smooth again. Pop back in the fridge until you are ready to serve.
To make the eyes balls, knead the white fondant and roll into small balls approx. 3-4cm in diameter. Roll small pea-sized balls of the coloured fondant and pop onto each eye-ball, press down to smooth it onto the white fondant. Finish with a small ball of black fondant on top of the coloured fondant. Finally use the red decorating icing to draw squiggly lines onto the eyeballs to look like veins. Leave the eyeballs to firm up until you are ready to finish the cake.
Just before serving the cake, roll out the back fondant to create a sausage shape and pop around the top edge of the cake, use any leftover black fondant to create 2 handles and attach to the side of the cauldron using cocktail sticks to secure them in place.
Lift the jelly out of the cake tin using the clingfilm and tip onto the top of the cake, if doesn’t need to be smooth as it’ll look like bubbles. If you have made jelly bubbles, use these to fill in any gaps in the jelly and pop on top of the jelly. Finally pop on the eyeballs!
Wow your Cauldron cake is now ready to serve and impress your guests!