Beat the softened butter, sugar and salt till fluffy.
Fold in the flour till all combined.
Shape the batter into a log and wrap with a clingfilm.
Chill the dough for at least an hour or more if possible.
Preheat the oven to 180 degrees. Line a baking pan with parchment paper.
Take the dough from the fridge, remove the film and slice them into 1/2 inch thick cookies - makes 12 cookies roughly. Line them up on the tray.
Bake for 12 to 15 minutes till just set. The cookies will still be soft. Allow to cool on the pan for five minutes before transferring them to the rack to cool completely.
Notes
The darker the brown sugar used, the color of the cookie will change.