Preheat oven to 350 degrees. Line a large baking sheet with parchment paper.
Add all of the dry ingredients(except chocolate) to large bowl, or stand mixer. Flour, baking soda, brown sugar, corn starch, salt, and white sugar. Mix until well combined.
Add the egg, egg yolk, butter, and vanilla to dry ingredients. Mix well until combined.
Crush your chocolate bars in a plastic baggy. Make sure not to crush the chocolate too much. Big chunks are fine.
Add chocolate chunks to dough. mix the chocolate into dough until it is distributed evenly and mixed in well.
Scoop out cookie dough with ice cream scoop or a tablespoon sized spoon.
Place on lined baking sheet. Bake for 12-14 minutes. Don't over cook them. They will appear to be very soft when done, but they will continue to cook as they cool down.