Preheat the oven to 350°F and line a baking sheet with parchment paper. Set aside.
In a stand mixer fit with a paddle attachment beat the butter and sugar until light and fluffy, about 3 minutes. Add in the egg and vanilla extract. Scrape down the bowl and beat until everything is well mixed.
Add the flour, baking soda, and salt to the wet mixture and mix until just combined. Remove the bowl from the stand mixer and add in the white chocolate, macadamia nuts, cranberries and oats. Using a rubber spatula, fold in the ingredients until everything comes together.
Using a medium sized cookie scoop, drop the cookie dough onto the prepared baking sheets into rounded balls about 2 inches apart each. Bake at 350°F for 12-14 minutes, or until the edges are just golden brown, but the inside of the cookie is still doughy–it will continue to bake as it cools! Enjoy with a glass of milk!