Stir the flour, baking soda, cornstarch, and salt together in a small bowl and set aside.

In a large bowl, cream the butter and sugars together until no lumps remain.

Add egg. egg yolk, and vanilla. Mix well.

Add the dry ingredients to the wet ingredients and mix together.

Gently fold in the brownie brittle making sure to not crush it too small.

Cover and place in fridge for at least 2 hours, preferably over night.

*When ready to bake*

Preheat oven to 350°

Take the dough out of the fridge and scoop onto parchment lined cookie sheet.

Top each mound of dough with 9-12 chocolate chips. Or as many as you want.

Bake for 9-11 min. Do not over-bake. They will look underdone and that's okay.

Let cool on cookie sheet for 10 min and then move to a wire rack to completely cool.

Repeat until all dough is used.