Mix flour, salt, and starch in a bowl, set aside.
On a separate bowl, using electric mixer, cream/combine butter and sugars, then beat in eggs and extract
Beat in flour mixture a little at a time
Chill in the fridge for 2 H
Scoop dough per 1 tbsp, shape into disks, place on non stick cookie sheet
Bake cookies on preheated 350F for 8-10 mins
Cool on rack
Once cookies cooled, spread fluff on one, and sandwich with another cookie.