Preheat oven to 350 (175C). Line cookie tray with parchment paper.
Melt butter in microwave for 30-40 seconds, until it is in a liquid form.
In a medium mixing bowl add butter and sugar. Using a Hand beater cream together till it becomes pale in colour.
Add egg and vanilla extract and beat until you can't see egg anymore. Don't over beat the mixture or the cookies will lose their softness.
Sift flour, baking soda and salt to mixture. Mix ingredients together with a wooden spoon until it is crumbly. Then knead dough with hands until it creatures a ball. Add in dark and white chocolate and dried cranberries
Roll dough into 15 same sized balls and place evenly spaced onto cookie tray. Flatten lightly with hand. Cook in oven for 12-13 minutes. They should be a lightly tanned colour when removed. Cool on tray for ½ an hour. Or just dig in.