This is my grandma's recipe, the best shortbread cookies I've ever tasted! You can add in chocolate chips or toffee bits to give more of a sweet and salty flavour. I've even used it as a pie crust for apple pie.
Cream butter and sugar together very well. Add flour and keep mixing until the dough comes together. Roll into a log, wrap in plastic wrap and chill about 10 minutes.
Roll log in brown sugar and then slice cookies from log and place on greased cookie sheet. Bake 45 minutes or until very light golden brown. Cool on sheet for a few minutes and then move to rack to cool completely.