Preheat oven to 160°C fan forced. Line two baking trays with baking paper.

If the macadamias aren’t already toasted, spread them on a tray and bake for 5–7 minutes, until lightly golden. Set aside to cool.

Place butter in the Thermomix mixing bowl and melt 2 min/50°C/speed 2. Add brown sugar and caster sugar, then mix 20 sec/speed 4.

Add the egg and vanilla. Mix 10 sec/speed 4.

Add flour, baking powder, bicarbonate of soda and fine salt. Mix 15 sec/speed 4. Scrape down the bowl and mix for a few more seconds if needed, just until the flour is incorporated.

Set aside a handful of each chocolate and some macadamias for the tops. Add the rest to the mixing bowl and mix 10 sec/reverse/speed 2. Finish folding through with the spatula if needed.

Roll heaped tablespoons of dough into balls. Place them about 5 cm apart on the prepared trays and gently flatten to about 1 cm thick. Press the reserved chocolate and macadamias into the tops.

Bake for 12–15 minutes, until the edges are set but the centres are still a little soft. Sprinkle with a few flakes of sea salt, then leave on the trays for 15 minutes to firm up.