Make the pudding: Place the sugar, cocoa powder and corn starch in a pot and mix to combine. Gradually add the milk, stirring to combine. Set to low heat and bring to a boil. Boil for 2 minutes, stirring constantly, until thickened. Remove from the heat, pour into a bowl, add the vanilla extract and stir to combine. Cover the surface with a sheet of plastic wrap and place in the fridge until chilled.

Make the buttercream succulents: Spread some buttercream onto the surface of a flower nail, a tool that you use when piping buttercream roses etc. Place a square of parchment paper on top. Use a variety of piping tips to pipe the succulents of your choice onto the square of buttercream. This recipe used #67, #102, #102, #104, #18 and small, round tips for the cactus details. Slide the square of parchment paper onto a flat tray and transfer to the freezer until the succulents are very firm.