Preheat the oven to 350 F. Line a 12 cup muffin pan with paper liners. In a medium bowl, whisk together flour, salt, and baking soda.
In a large bowl, combine butter and sugar until fluffy. Add in egg and vanilla extract, mix until smooth. Add in the flour mixture, and mix until it is fully combined. Fold in the cranberries and white chocolate chips.
Evenly divide the cookie dough between the prepared muffin cups. Bake for 15-20 minutes.