To prepare a ultimate high altitude chocolate chip cookies recipe, preheat the oven to 350 degrees. Line two cookie sheets with parchment paper and set aside. Sift the flour, baking powder, sugar and salt into the bowl of an electric mixer and beat on medium speed until the mixture is light and fluffy, about 2 minutes. Gradually add the milk, beating after each addition until no streaks remain. Fold in the chocolate chips. Spoon the dough onto the prepared baking sheets and bake for 12 to 15 minutes or until cookies are lightly browned. Let the cookies cool on the baking sheet for 5 minutes before transferring to wire racks to cool completely.