Preheat the oven to 180°C and line a baking tray with baking paper.
Melt the chocolate pieces and butter in the microwave or on the stove top and allow to cool.
In a mixer, beat together the eggs, sugar, and vanilla essence until thick and pale.
Pour the melted chocolate into the beaten eggs and sugar. Stir through before adding the bourbon.
Sift in the flour and baking powder. Stir through before adding the chopped chocolate and macadamia nuts, and mix until combined.
Using an ice cream scoop, scoop the mixture onto the lined baking trays. The cookies will flatten out when baked.
Bake in the oven for 8–9 minutes and cool on the tray before transferring to a cooling rack. If you put the cookies onto the cooling rack while hot, they will become marked by the wires from the rack.