Preheat oven to 350℉. Whisk together flour, baking soda, cinnamon and salt. In a large bowl using a wooden spoon or stand mixer fitted with a paddle attachment cream together butter and both sugars. Add eggs one at a time, then add vanilla mixing until fully incorporated. Stir in flour, then add oatmeal, white chocolate and bluberries, mixing until just combined.
Line baking sheets with parchment and using approximately 2 tbsp of dough place onto sheet leaving at least 2 inches between cookies. Flatten each cookie slightly with the palm of your hand or bottom of a glass. Bake for approximately 12 minutes in centre of oven. Remove from oven and allow to rest on tray for 3-5 minutes. Remove with a spatula to a cooling rack.
It is best to bake only one or two trays at a time in the centre of the oven.