Preheat oven to 325° F. Prepare baking sheets with a silicone mat, parchment paper, or leave plain.
In a stand mixer, combine butter, sugar, and brown sugar until light and fluffy. Add egg and vanilla until combined.
Add in gluten free flour, oat flour, guar gum, cinnamon, salt and baking soda and stir until everything is combined.
Using a spoon instead of the mixer, gently add in the oats, cranberries, and white chocolate chips.
Shape the dough into balls slightly smaller than a golf ball and place on baking sheet about 2 inches apart.
Bake for 9-10 minutes. Be careful not to overbake, a slightly uncooked center is perfect for these cookies! Remove from oven and allow to cool slightly before transferring to a cooling rack. Repeat with remainder dough.
Store in airtight container.