Preheat the oven to 375. Line two large baking sheets with parchment or spray with cooking spray.

In a large bowl or the bowl of a stand mixer, cream together the butter and brown sugar until light and fluffy. Add the eggs, milk, and vanilla, and mix to combine. Add the oats, flour, whole wheat flour, baking soda, salt, and cinnamon, and mix until combined. Fold in the blueberries with a rubber spatula.

Scoop tablespoon sized balls of dough onto the prepared baking sheets. Bake 10-12 minutes or until lightly golden brown around the edges.