Preheat oven to 350 degrees and line two cookie sheets with parchment paper.
Using a medium bowl, whisk together the flour, cornstarch, baking soda, and salt until combined.
Using a large bowl, cream together the butter, light brown sugar, and sugar until light and fluffy.
Add in the egg and cream everything together.
Slow mix in the dry ingredients until the dough has formed.
Fold in 1 C of the dark chocolate chips, dark chocolate chunk, chopped walnuts, and dried cranberries.
Mix the remaining 1 C of the dark chocolate chips, dark chocolate chunks, chopped walnuts and dried cranberries.
Scoop 2 tablespoons of cookie dough onto the cookie sheet and bake for 6 minutes.
Remove from oven and carefully sprinkle on some of the topping mixture onto the cookies.
Place back into the oven and continue to bake for another 4-6 minutes or until lightly golden brown.
Enjoy!