Pre-heat the oven to 350 degrees F and line two cookie sheets with parchment paper.
Melt the butter and allow it to cool slightly so it doesn't melt the chocolate chips with you mix it in.
Put all the dry ingredients, including the chocolate chips, in the bowl of a stand mixer with the paddle attachment connected. Give it a little mix on low just to bring everything together.
In a small bowl, beat the egg and vanilla together.
Turn on the mixer and pour in the melted butter. Allow it to mix slightly before adding the beaten egg and vanilla. You will likely notice a bit of dry ingredient on the the bottom of the bowl. Now add the milk, one tablespoon at a time. The batter should be quite thick but have no excess dry ingredients on the bottom of the bowl.
Use a mini ice cream scoop if you have it to spoon tablespoon size dollops onto your cookie sheet. Bake for 15-17 minutes at 350 degrees F until lightly golden brown. Your oven may vary from mine so start checking the cookies at about 13 minutes.