Preheat oven to 325. Line bang sheets with parchment paper
Whisk flour, baking soda and salt in a bowl, set aside
In a large bowl beat butter with both sugars about 2 minutes until light and fluffy
Add egg, egg yolk and vanilla and beat in
Add flour mixture and stir until well blended but not overmixed
Fold in heath chunks and cocoa krispies, being careful not to crush cocoa krispies
Roll dough into 1 inch balls, press top slightly to flatten, place 2 inches apart on prepared pans
Bake for 10 to 12 minutes just until light golden, don't over bake for chewy cookies. Cool 1 minute in pan then transfer to wire racks to cool completely
