Whisk the melted butter and MiniMakes sugar sachet, then mix in the egg until well combined. Mix in the MiniMakes cookie mix to form a smooth dough and set in the fridge for 1 hour to chill.

Meanwhile, preheat your oven to 160°C and prepare a small square cake tin (20cm x 25cm) with Spray & Cook.

Press the cookie dough in the base of the pan and bake for 20 minutes until lightly golden. Set aside to cool.

To make the topping, melt the butter in a saucepan over medium heat. Add the sugar and milk and stir until the sugar has melted, then bring to a boil for 2–3 minutes, without stirring. Remove from the heat and stir in the peanut butter. Using a wooden spoon, beat in the icing sugar until the mixture is smooth.

Pour the peanut butter mixture on top of the cooked cookie dough base in the tin, smooth the top with a spatula and leave to cool slightly

Melt the chocolate in a double boiler or glass bowl placed over a saucepan of simmering water until smooth. Spread the melted chocolate, reserving about two tablespoons, over the peanut butter layer and refrigerate until set.

Cut the millionaire’s shortbread bars into bars or desired shapes with a sharp knife, then drizzle over the reserved melted chocolate and sprinkle with sea salt.

Store in an airtight container in the refrigerator.