Preheat oven to 350°F. In a large bowl, combine the butter and sugars. Beat until smooth, about 3-4 minutes. Add the eggs and vanilla and beat until smooth again.
In a separate bowl, stir together the flour, baking soda, salt, cinnamon, and oats. Gradually add this mixture to the wet ingredients, half at a time. Stir until fully combined. Add the cranberries and chocolate and stir to mix throughout.
Using a medium-size scoop, drop the dough onto a large baking sheet lined with parchment paper or a silicone mat. (For larger cookies, make the dough balls golf-ball size and put just 6 on a baking sheet at a time.)
Bake smaller cookies for 8-9 minutes. (Bake larger cookies for 14-16 minutes.) Remove from the oven before the cookies are browned and when they still look soft, but not wet in the center. Let the cookies cool on the tray for at least 5 minutes; this will allow them to finish baking without overcooking.
Transfer to a cooling rack and then store in an airtight container. The cookies will keep well for several days. Enjoy!
Notes
semi-sweet chocolate or dark chocolate chips work may be substituted