Preheat oven to 350 degrees F. Lightly grease cookie sheets.
In a large bowl, cream butter, granulated sugar, and brown sugar until light and fluffy. Add eggs and beat until smooth. Stir in flour, baking soda, baking powder, and ground cinnamon.
Add the rolled oats and continue stirring until combined. NOTE: If you are adding nuts, raisins, or chips, add them now. Place round tablespoons of dough on prepared cookie sheets. The mounds of dough should be no larger than a walnut.
Bake 9 to 12 minutes or until light brown and bottoms are golden (cookies should not get brown). Remove from oven and cool on wire racks.
Old Fashioned Oatmeal Cookies Recipe: https://whatscookingamerica.net/Cookie/OatmealCookie.htm