Preheat oven to 325. Line baking sheet with parchment.
Cream together shortening, butter & brown sugar.
Add in egg yolk and vanilla. Reserve egg white.
Add flour and salt to bowl, mix thoroughly.
Roll into small balls, slightly under 1". Dip balls in egg white, then roll around in nuts.
Place on to prepared baking sheet, leaving about an inch between each cookie.
Bake 5 minutes, then pull cookies out of oven. Working quickly, use your thumb to dimple the top of each cookie. Return cookies to oven, and bake another 8 minutes.
Pull cookies out of oven, let rest on sheet pan a few minutes, then allow to cool completely on wire rack.