1. Preheat oven to 180°C. Grease a 20cm square cake tin and line the base with baking paper.
2. Place the brownie mix, butter, eggs and water into a medium mixing bowl. Mix with a wooden spoon until well combined and smooth.
3. Spread the mixture in the prepared tin and bake for 30-35 minutes or until a skewer inserted into the middle comes out clean. Let cool completely in tin.
4. Once cool, combine chopped white chocolate and cream in a small saucepan over low heat and stir until smooth. Stir in peppermint essence. Let cool for 5 minutes and then pour over cooled brownie base, spreading it out in an even layer. Refrigerate until firm, about 1 hour.
5. Once firm, make the chocolate glaze by combining frosting mix, butter and boiling water in a small bowl. Stir until smooth and shiny then pour over the brownie in an even layer. You may need to add extra water to get a pouring consistency.
6. Sprinkle crushed candy cane over the top and refrigerate for 1 hour before removing from the tin and cutting into slices.