Preheat oven to 350℉ to heat-treat the flour to make it safe to consume. Line a rimmed baking sheet with parchment paper and set aside. Add the flour to the baking sheet in an even layer and bake for 5-7 minutes. Set aside to let cool.

Melt the butter in a medium saucepan or skillet over medium heat. Once it has melted, start whisking constantly for 3-4 minutes. Watch carefully, as it can burn easily. The butter will begin to bubble, get a little foamy, and develop a golden brown color with a nutty aroma. Once the little brown bits start to appear, keep cooking for about a minute, until the butter is golden brown, but not too dark. Remove from heat immediately and transfer to a medium heat-safe mixing bowl. Let cool for 5-10 minutes.

While butter is cooling, add the pumpkin pie spice, cinnamon, and salt to the flour (I just add it right on the baking sheet to avoid dirtying another bowl!), and stir together with a spatula or spoon until combined.

Once butter has cooled for a little bit (it will still be warm), add the dark brown sugar and granulated sugar. Whisk until combined. Add the vanilla and milk and whisk until smooth. Add the dry ingredients to the wet and mix with a rubber spatula until incorporated. Let the dough rest for 10 minutes to allow the flour to absorb the wet ingredients. Once dough has rested, fold in the white chocolate chips. It's okay if the dough is still a little bit warm - the white chocolate chips will get a little bit gooey and melty! Enjoy!