Preheat the oven to 350. Line a 9 x 9 baking dish with foil or parchment, and set aside.
In a large bowl or the bowl of a stand mixer, mix together the melted butter, sugar, and brown sugar. Add the egg, egg yolk, and vanilla, then mix until combined.
In a small bowl, whisk together the flour, baking soda, and salt. Add the flour mixture to the wet ingredients, and mix until just combined. Fold in the cranberries and white chocolate chips. Spread the cookie dough in the prepared pan, into an even layer.
Bake 40-45 minutes, or until golden brown, and a toothpick inserted 2 inches from the side of the pan comes out clean. Cool completely before cutting and serving.