Preheat the oven to 350°F and line a baking tray with parchment paper. Set aside.
Whisk together brown sugar and butter.
1/2 cup butter, 1/3 cup brown sugar
Add in vanilla and sweetened condensed milk. Continue whisking.
1 tbsp vanilla, 2/3 cups sweetened condensed milk
Add in flour, baking powder, cornstarch, and dark cocoa. Fold using a spatula until just combined. Do not overmix!
1 cup all-purpose flour + 2 tbsp, 2 tbsp dark cocoa powder, 1 tsp baking powder, 2 tsp cornstarch
Toss in white chocolate chips and fold.
1/2 cup white chocolate chips
Bake 6 cookies at a time for 7-9 minutes. The inside will look super soft, but the outside will have a slight crisp edge
Remove from oven and allow to cool on the pan. As they cool they will continue to bake. Now would be the time to add extra chips on top if you'd like. Enjoy!