Method

• 1.
  Grease a 1L (4-cup capacity) terrine mould and line the base with baking paper.
• 2.
  Whiz shortbread in a food processor to crumbs. Add butter and whiz to combine. Press evenly into base of the mould.
• 3.
  For spearmint caramel, place cream, peppermint essence and spearmint in a pan over medium-low heat. Bring to the boil, then remove from heat and set aside for 20 minutes to infuse. Strain, discarding mint leaves. Melt sugar in a clean frypan over medium-high heat, swirling pan, for 5 minutes or until a golden caramel forms. Add butter and swirl pan, then add infused cream, swirling to combine. Remove from heat and pour evenly over shortbread. Set aside for 30 minutes to firm up slightly.
• 4.
  For mint ganache, place all ingredients, except chocolate, in a pan over medium heat and bring to just below boiling point. Remove from heat. Set aside for 20 minutes to infuse. Remove mint leaves and discard. Return pan to medium heat, and bring to a simmer. Place chocolate in a heatproof bowl and pour over cream mixture, stirring until melted and smooth. Pour over caramel layer. Cover and chill for 4 hours or until set.
• 5.
  For the milk chocolate glaze, place the chocolate and oil in a heatproof bowl set over a pan of simmering water (don’t let bowl touch water), stirring until melted and smooth. Set aside to cool.

• 6.
  Carefully turn out bar onto a well-oiled rack set over a tray, so that the biscuit base sits on rack and ganache layer is facing up. Pour melted chocolate over top and sides, smoothing with a palette knife. Chill for 15 minutes to set.
• 7.
  Dust slice with cocoa, then, using a hot sharp knife, cut into slices to serve.