Mix the flour, baking soda, cornflour and salt in a bowl
In another bowl mix the melted butter, brown sugar and castor sugar until all lumps are gone
Mix in the egg and egg yolk, then the vanilla extract
Pour the wet ingredients into the dry ingredients and mix together
Break up the chocolate and add it in
Crush the potato chips and combine
With an ice-cream scoop, roll into balls
Cover and chill in the fridge for a few hours
Before baking, add extra chips on top for added crunch
Bake at 170°C for 12-15min. Remember they will continue to bake on the cookie sheet so it's ok if they look soft when you first take them out
