Prepare brown butter: In a medium saucepan, melt the butter over medium heat. Once it bubbles vigorously, cook 6–8 minutes, swirling occasionally, until bubbles subside, foam forms, and toasty brown flecks appear. As soon as you get these visual cues and a nutty fragrance, pour the butter into a heatproof bowl, scraping the bottom of the bowl, and allow to cool for at least 20 minutes. You should have about 240g of browned butter.
In a medium bowl, whisk together flours, spices, salt, baking powder, and baking soda.
Using the paddle attachment of a stand mixer, cream together both sugars, the molasses, and the cooled brown butter until it pales in colour and is just slightly fluffy - about 2-3 minutes on medium speed.
Add eggs one at a time, mixing thoroughly after each. Scrape the bowl, then continue mixing until very smooth.
Mix in the flour mixture until just barely incorporated with floury bits remaining, then paddle in the white chocolate until evenly mixed. Use your hand or a spatula to scrape the bottom of the bowl to ensure no gooey bits remain.
Portion the cookies into 100g balls, and rest, covered, in the fridge overnight.
The next day, preheat the oven to 180℃/350℉, and roll the cookies in sugar, making sure the whole exterior of the cookie is sparkling in sugar.
Bake the cookies for about 18 minutes, rotating halfway through baking.
While taking the cookies out of the oven, slam the hot tray onto your bench to flatten your cookie ever so slightly.
