Preheat the oven to 350 degrees. Prepare a baking sheet with parchment paper.
Whisk together the flour, baking powder, and salt. Set aside.
In a large mixing bowl, cream butter and sugar until fluffy.
Add the eggs and vanilla, mixing well.
Add the flour mixture to the batter, scraping down the sides as needed.
Stir in the white chocolate chips, cranberries, and walnuts.
Using a medium cookie scoop, drop the cookie dough about 2 inches apart onto the prepared baking sheet.
Bake for 10 to 12 minutes. Allow the cookies to cool on the baking sheet for 5 to 7 minutes before transferring the cookies to a wire rack to cool completely.