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.
2/3 cups sweetened condensed milk, 1 tbsp vanilla
Add in flour, baking powder, cornstarch, and baking soda. Fold using a spatula until just combined. Do not overmix!
2 cups all-purpose flour, 1 tsp baking powder, 1 tbsp cornstarch, 1/2 tsp baking soda
Toss in chocolate chips and fold.
3/4 cup semi-sweet chocolate chips
Bake 6 cookies at a time for 7-9 minutes. The outside will look a light brown, and the inside will look soft.
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!