Cream butter, add in icing sugar
Beat in yolk one at a time, followed with essence
Add in flour, knead
Knead in grated cheese
Roll flat dough and cut into sticks/rectangle
Brush with yolk
Top with more grated cheese and sprinkle with salt
Bake on preheated 350 F for 8-10 mins (depending your oven it can be 10-12 mins)
Cool on pan for 5 mins, then move to rack