Using mixer, whisk on medium:
285g (1.25 c) brown sugar
115g (½ c) white sugar
Stream in:
280g (1.25 c) melted butter
2 eggs + 3 egg yolks
Switch to paddle and add in:
230g (1.5 c) cake flour
275g (2 c) all purpose flour
5g (1.5 tsp) salt
8g (2 tsp) cornstarch
6g (½ tsp) baking soda
Mix in
165g (2 c) walnuts, rough chopped and toasted
450g (1 lb) 60-70% dark chocolate, rough chopped
Wrap and chill in he refrigerator for at least 45 minutes. Scoop 6 oz for each cookie. Bake at 425 F for 10-13 minutes.