Heat oven to 400°F.
Combine the flour, baking powder, salt, and 1 tablespoon of sugar with an electric mixer.
Add the cold butter and mix just until the butter is coated with flour (butter chunks should remain fairly large).
Add cranberries and white chocolate.
Stir gently. Add in 2/3 cup of the buttermilk.
Stop mixing when dough begins to pull away from the sides of the bowl.
Quickly shape dough into a ball and pat into a circle about 1/2 inch thick.
Cut into 8 pie-shaped wedges.
Place wedges on a baking sheet lined with parchment paper.
Brush tops with remaining buttermilk and sprinkle generously with the 2 tablespoons sugar.
Bake 15–20 minutes.