In a large bowl, cream the butter and sugar for about 3-5 minutes until creamy.
Add egg yolk, salt, and vanilla extract and mix until well combined.
Add the flour to the butter mixture.
Incorporate the flour using the mixer or a spatula.
Add the chopped chocolate and cranberries.
Fold them in until well distributed.
Wrap the dough in plastic wrap and shape it into a log about 2 inches (5cm) in diameter.
Chill the dough for at least 2 hours and up to 2-3 days.
Preheat the oven to 325ºF (165ºC) and line a large baking sheet with parchment paper.
Slice the cookies into ¼ inch (6mm) thick cookies.
Place the cookies on the prepared baking sheet, leaving space between them.
Bake for about 15 minutes or until slightly golden on the edges.
Let the cookies cool on the baking sheet for 5 minutes.
Cool completely on a cooling rack.