In the bowl of a stand mixer fitted with a paddle attachment (or using an electric hand mixer), combine melted butter, brown sugar, and sugar until light in color.
Add egg, egg yolk, milk, and vanilla. Mix on low speed until well combined. Add in flour and salt. Stir together until there are no longer any dry streaks of flour. Scrape down bowl as needed.
Fold in cranberries, white chocolate chips, dark chocolate chips, and chopped pistachios. Cover bowl with plastic wrap and let chill in the fridge for one hour.
Preheat oven to 350° F. Use a large cookie scoop to portion out chilled dough. Space cookie mounds about 2-inch apart on parchment lined baking sheet.
Bake for 10-12 minutes until edges are set. Cool in pan for 5 minutes before unmolding and transferring to wire racks to cool completely.