01 - 
                Preheat oven to 350°F. Line baking sheets with parchment.
              
              
              
                02 - 
                Beat cold butter and sugar. Add vanilla and egg, mix briefly.
              
              
              
                03 - 
                Mix in flour, cornstarch, baking soda and salt until soft dough forms.
              
              
              
                04 - 
                Beat in chocolate and walnuts briefly.
              
              
              
                05 - 
                Drop 1/4 cup portions of dough. Keep shape rough.
              
              
              
                06 - 
                Bake 12-14 minutes until golden. Cool fully. Top with sea salt.