Spread the flour out on a large rimmed baking sheet or pan and place in the preheated oven for 5 minutes. Remove it to a bowl and let it cool completely. If the flour looks a bit lumpy, whisk it briefly before you add it to the dough mixture.
In a mixing bowl with an electric mixer, combine the butter with the brown sugar. Beat for 3 to 4 minutes, or until light and fluffy. Add the milk, vanilla, and salt; beat until well blended.
When the flour has cooled completely, add it to the creamed mixture. Beat until blended. Fold in the chocolate chips.