Whisk the flour, baking powder, baking soda and salt together until evenly blended, then set aside.
Put the softened butter and both sugars in the stand mixer bowl and use the paddle attachment to beat just until creamy. Alternatively, you can do this with a big scraper or a wooden spoon.
Add the milk powder and stir with the paddle (or your spoon) until blended, than add the egg and vanilla and stir just fully blended. The goal is to just mix everything without dissolving the sugar or whipping in a lot of air. This helps cookies spread less.
Add the flour mixture and stir until it's mixed in, scraping the sides of the bowl and pushing the dough together. Add the chocolate chips.
Using a medium size cookie scoop (about 1 ½ tablespoons), scoop up balls of dough. Chill the dough balls while the oven preheats.
When ready to bake, preheat oven to 350 degrees F. Bake on a parchment lined baking sheet for about 10-12 minutes for medium size scoop cookies
Let cookies cool on the sheet for about 10-15 minutes, then transfer to a wire rack and let cool completely.