Preheat oven to 350F.
In a bowl, combine flour, xanthan gum (if using), baking soda, salt and cinnamon. Set aside.
In a large bowl, beat together sugars and butter until creamed and smooth.
Then, add in the egg and vanilla, and mix until combined.
Stir in oats, chocolate chips, and cranberries until fully incorporated.
Spoon rounded tablespoons of dough onto an ungreased cookie sheet.
Bake 10-12 minutes at 350F. Cool on baking sheet for 1-2 minutes before transferring to wire racks to finish cooling.