Preheat the oven to 350° F. Line a cookie sheet with parchment paper or a silicone baking mat and set aside.
In the bowl of a stand mixer or with an electric hand mixer, combine the butter and brown sugar until light in color and fluffy in texture.
Add in the eggs and milk, mixing thoroughly.
Add the whole wheat flour, rolled oats, salt, baking powder, cinnamon and baking soda to the mixer and mix until a soft and almost sticky dough forms.
Mix in the raisins until evenly distributed.
Scoop 1 1/2 tbsp of dough ( #40 scoop) for each cookie. Flatten just slightly and add extra raisins to the top, if desired.
Bake at 350° F for 9-11 minutes or until the cookies have spread slightly and no longer look wet and glossy on the top.
Allow the cookies to cool on the pan for at least 15 minutes for them to set up before enjoying.