Preheat oven to 350 degrees F.
Adjust the oven rack to the middle of the oven, preheat the oven to 350ºF, and line cookie sheets with parchment paper.
In a medium bowl, whisk together the all-purpose flour, unsweetened dark cocoa powder, baking soda, and Kosher salt. Set aside.
In a medium size mixing bowl if using a hand mixer or stand mixer fitted with the paddle attachment beat the unsalted butter, light brown sugar together on medium-high speed until light in color and fluffy in texture.
Add in the eggs and vanilla extract and continue to mix until well blended. Scraping down the sides of the bowl as needed.
Working in batches, gradually add the whisked dry ingredients until combined.
Fold in the dark chocolate chips and dried cranberries.
Using a spoon or cookie scoop (I used a large cookie scoop), drop the cookie dough onto the lined baking sheets, leaving at least 1 inch apart between each cookie.
Lightly sprinkle the raw cookies with a small pinch of the flake salt.
Bake for 10-15 minutes at 350ºF or until the cookie is firm around the edges. Cooking time can vary.
Remove from oven and allow to cool for 5 minutes before transferring them to a wire cooling rack to finish cooling.
Keep the cookies stored in an airtight container in the refrigerator for up to a week or freeze for up to six months.