In stand mixer, cream butter and sugars until fluffy.
Add eggs, milk, and vanilla, beat until everything is fully incorporated and smooth.
In a large bowl, mix together remaining ingredients. Slowly add this dry mix to the mixer bowl, and carefully mix until well incorporated and smooth.
Chill dough for 1 hour.
Preheat the oven to 375F (190 C), line baking sheets with parchment paper.
Roll 1" balls out of the cookie dough.
Arrange dough balls on baking sheets leaving at least 2" between cookies - they flatten out a fair amount.
Gently press the tops of each slightly - flatten JUST enough to prevent the dough from rolling.
Bake for 11-13 minutes. Cookies will look puffy, but flatten out as they cool. Do not overbake!