Brown butter, cool, hand mix in sugar, then egg + vanilla. Mix in whisked Dry, adding choc towards end. Form 8 x 155g (1/2 cup) discs 3.75cm/1.5" thick. Fridge 12 -24 hrs. Bake from fridge cold 4 at a time, 180°C/350°F (170°C fan) 17 min, top with more choc while hot if desired. Cool 20 min on tray, attack!

Simmer to brown - Put the butter in a silver saucepan or small pan over medium high heat. Once melted, let it simmer (as in, bubbling) for 4 to 5 minutes, stirring every now and then, until it gets real foamy, you see little golden specks (wade through foam to see) and it smells nutty & extra buttery.

Cool - Immediately pour into a heatproof bowl, including all those golden specks. Cool to room temperature (~45 minutes), cool enough so it won't melt the choc chips (Note 4)

Whisk Dry ingredients in a separate bowl.

Mix Wet - To the browned butter, add both sugars and mix with a wooden spoon. Add the egg, yolk and vanilla. Mix until smooth - it will look caramel.

Finish dough - Add the Dry ingredients and mix until the flour is mostly incorporated. Add the choc chips and stir until the flour is fully incorporated.

Make dough discs - Measure out 8 x 155g (5.3 oz/ 1/2 cup) portions of dough, roll into a ball then shape into a 3.75cm/1.5" thick round disc. Place in a very airtight container. (Note 5 for smaller cookies)

Fridge 12 hours - Refrigerate for 12 hours, up to 48 hours (Note 6 for different chill times).

Preheat oven to 180°C/350°F (170°C fan-forced). (Note 7)

Place 4 fridge-cold cookies 7.5 cm/3" apart on a tray lined with baking paper/parchment paper. (Note 8 baking tips)

Bake for 17 minutes or until the edges are golden and the surface is just set (ie not melty raw dough) but still pale.

Decorate and cool - Working quickly, press extra choc chips on the surface (Note 9), then cool on the tray for 20 minutes - finishes baking, edges crisp more and they get more golden all over.Tip: While hot, you can also reshape with a rubber spatula or similar into a tidy round shape.

Grab now - peak eating moment! Or, transfer to a rack to cool fully before storing in an airtight container.