• Preheat the oven to 180 degrees Celsius/ 350 degrees Fahrenheit. If using a convection oven (fan-forced), preheat it to 160 degrees Celsius/ 320 degrees Fahrenheit. Line 2-3 baking trays with parchment paper.
• Chop the chocolate, walnuts, and cranberries. Set aside.
• Cream the sugar and the very soft butter, about 3 minutes. Add the egg and the vanilla extract, and cream again.
• Combine: Mix flour, baking powder, and baking soda in another bowl. Combine with the butter-egg mixture. Add the chopped ingredients and oats. Mix in with a spoon.
• Scoop small amounts of dough about the size of a walnut, and place them on the prepared baking trays leaving some space between them, as they will spread during baking. Press each one lightly with a spoon to make them flatter.
• Bake for 11-12 minutes until slightly golden. Leave to rest on the tray for 5 minutes, then transfer to wire racks to cool completely.

Drizzle:

• Melt the chocolate: Melt the chopped white chocolate au bain-marie (or microwave it) once the cookies are completely cool.
• Drizzle onto the cookies. For easy drizzling, spoon the melted chocolate into a small zip lock bag. Cut a tiny hole in the corner of the bag and drizzle the chocolate back and forth over each cookie.
• Leave until the chocolate is set.