Whisk together the flour, baking soda, cinnamon and salt in a medium bowl.
Cream the butter, sugar, and brown sugar in a separate bowl with an electric mixer or in the bowl of a stand mixer fitted with the paddle attachment, for 2-3 minutes, until it's light and fluffy.
Add the eggs one at a time, beating well after each addition then add the vanilla and continue to beat for 1-2 minutes.
Slowly add half of the dry ingredients and turn the mixer on low to incorporate into the dough, then turn the mixer up to high to combine fully. Repeat with the second half of the flour mixture.
Stir in the oats, white chocolate chips, and dried cranberries using a rubber spatula or wooden spoon. Cover thee dough with plastic wrap and chill in the fridge for at least 30 minutes, or up to 3 days (see notes).
Preheat the oven to 350°F and line a large baking sheet with parchment paper.
Use a medium (2 Tablespoon) cookie scoop to roll the dough into even-sized balls. Arrange them 2-3 inches apart on the prepared cookie sheet and bake in the preheated oven for 8-10 minutes, until the edges and top are just set.
Remove them from the oven and top them with additional cranberries and white chocolate (not necessary, but makes them look better). Cool the cookies on the baking sheet for 5 minutes then transfer them to a wire rack to cool completely.