Preheat oven to 180C/350F/Gas 4 degrees and spray three 9-inch cake pans with baking spray. Set aside.
Sift the flour, cocoa powder, baking powder, baking soda, and salt into a bowl. Set aside.
Using a medium saucepan over medium to high heat, combine the water and sugar.
Bring to a boil and stir until the sugar is dissolved. About 1 minute.
Whisk in the oil and peppermint extract.
Quickly whisk in the eggs to avoid them cooking into the chocolate mixture.
Gradually whisk in the dry ingredients until combined.
Divide the batter between the three cake pans and place in the oven to bake for 30-35 minutes or until a toothpick comes out clean.
Allow cakes to cool in the pans for 10 minutes, then remove from pans and place on a wire rack to cool completely before frosting.
Use a cake leveler to trim the cakes so that they are all flat and level for stacking.
To make the frosting, using an electric mixer beat together the cream cheese and butter until combined and smooth.
Gradually mix in the cocoa powder, peppermint extract, and salt.
Very slowly, beat in the powder sugar until combined.
Whisk in the heavy whipping cream until the frosting is smooth and fluffy.
Place 2 cups of the frosting in a large piping bag fitted with a star tip and set aside.
Place the first layer of cake onto a cake board.
Measure out 4-6 scoops of frosting using an ice cream scoop and use a spatula to evenly spread over the cake.
Add the next layer, and repeat the frosting. Add the final cake layer.
Use the remaining frosting to cover the top and sides of the cake.
Coat the bottom sides of the cake in the crushed candy canes.
To make the chocolate ganache, heat the cream in a small pan until steaming.
Place the chocolate chips into a heat-proof bowl and pour the cream over the top.
Allow to sit for 1 minute before whisking until smooth.
Pour ganache into the squeeze bottle and allow to cool for 10 minutes.
Squeeze the bottle of chocolate ganache around the top edges of the cake to form a drip effect.
Using the piping bag of frosting, pipe swirls around the top of the cake and place a mini candy cane on each one.