Combine the flour, salt, cinnamon, baking soda, and cornstarch in a bowl. Set aside.
1 ¼ cups all-purpose flour, ½ teaspoon salt, ½ teaspoon ground cinnamon, ¼ teaspoon baking soda, 1 teaspoon cornstarch
In a large bowl, beat the butter and brown sugar until light and fluffy.
1 cup brown sugar, ½ cup butter
Add in the egg, vanilla, and milk. Mix well.
1 egg, 1 teaspoon vanilla extract, ¼ cup milk
Slowly add the flour mixture to the butter mixture.
Mix in the rolled oats.
1 cup rolled oats
Add in the chocolate chips and mix just until they are mixed into the batter well.
1 cup mini chocolate chips
Cover and chill the dough for at least an hour and up to two days.
Preheat the oven to 375°F.
Let the dough sit out for a few minutes to soften a bit.
Roll batter into about one tablespoon-sized balls. Place them on an ungreased cookie sheet (covered with liner or parchment, optional). Space them about two inches apart.
Bake 8-10 minutes or until slightly browned.