Beat butter and brown sugar together until light and fluffy. Add vanilla, milk and eggs and beat until combined.
In a separate bowl, whisk together flour, baking soda, baking powder, salt and cinnamon. Slowly add to mixing bowl and beat just until incorporated. By hand, stir in oats, chocolate chips and M & M’s.
Drop dough by heaping tablespoons onto baking sheets. Bake at 375 degrees for 15-20 minutes, until lightly golden brown.
Cool on wire racks and store in airtight containers. Cookies can also be frozen.
