Premake the brown butter well in advance so that it is chilled.
Place the butter, sugars and vanilla into the Thermomix bowl and chop 10 sec/speed 5. Scrape bowl with a spatula and repeat until well combined.
Insert Butterfly. Whip 1 min/Butterfly/speed 4. Remove Butterfly.
Add remaining ingredients except chocolate and blend 10 sec/speed 6. Scrape down sides of bowl and repeat.
Fold through chocolate chips and nuts using a spatula.
Preheat oven to 170°C.
Line a baking tray and roll tablespoon sized balls of dough, arrange on tray. Press to flatten slightly.
Refrigerate for 30 minutes.
Bake 15 minutes until golden.
If you are feeling fancy, garnish with some edible gold leaf when cold. I use the gold leaf that comes in a jar, in pieces. The cookie is sticky enough to just press the gold leaf on top and it will stay. I initially used a paint brush, but it was easier just to use my fingers.