Melt 10 tbsp butter over medium heat until amber-colored with a nutty aroma. Pour into a heatproof bowl and refrigerate or freeze until solid.
Whisk together the flour, ground cardamom seeds, baking soda, and salt
Combine the remaining 6 tbsp of softened butter with solid browned butter, both sugars, and the lemon zest. The mixture should be slightly lighter in color, but not too fluffy.
Add the egg and the egg yolk. Mix until just combined.
Add the dry ingredients. Mix until starting to combine - some dry bits will remain
Add the white and chocolate chips, walnuts, and apple. Mix until fully combined.
Form dough into 50 g balls (about the size of a golf ball) - should yield 24-27
Place on a tray and chill in the refrigerator until firm - about 1 hour
Preheat oven to 375°F
Line a baking sheet with parchment paper and place cookie dough at least 2 inches apart
Bake for 15-17 minutes. Edges should be golden brown with soft and puffy center
Remove from the tray onto a wire rack to cool completely