Combine flour, baking soda, baking powder, and corn starch in a bowl
In another bowl, mix dark brown sugar and granulated sugar
Add cold egg and egg yolk to the sugar mixture
Stir in vanilla bean paste
Add cold unsalted butter to the wet ingredients
Combine wet and dry ingredients
Fold in semi sweet chocolate chips and milk chocolate chunks
Add espresso powder and salt
Chill dough before baking
Bake according to recipe instructions
