1. Preheat an oven to 180 degrees Celsius, or equivalent. Line a 28x18cm baking tin with parchment paper.

2. For the chocolate oat base: In a medium saucepan, over a medium heat, melt the butter, sugar and golden syrup together until the sugar is fully dissolved.

3. In a mixing bowl combine the oats, flour, and cocoa powder.

4. Pour the melted ingredients into the dry mixture and stir until evenly distributed and the mixture appears moist.

5. Transfer the mixture into the lined baking tray.

6. Bake on the middle shelf of the preheated oven for 15-20 minutes or until the surface appears slightly dry. Set aside while you make the mocha fudge layer.

7. For the mocha fudge icing: Place the icing sugar, butter, water and coffee essence in a medium-size heavy-based saucepan, heat gradually until fully combined, to a smooth consistency.

8. Spread the mocha icing evenly over the pre-baked base, using a spatula to spread it into an even layer, and refrigerate for 30 minutes, or until the fudge is set.

9. For the chocolate drizzle: Melt the chocolate in a bain marie (a bowl set over a saucepan of simmering water). Drizzle the melted chocolate over the surface of the mocha fudge layer. Refrigerate until the chocolate layer hardens.

10. To portion, remove from the fridge, wait 10 minutes and cut as desired into neat bars, squares or triangles with a very sharp knife.

Variation: You can omit the coffee flavour by replacing coffee essence with cocoa powder (or melted chocolate).