Start with one cup of sugar.
Add 1 to 2 Tablespoons of molasses ( depending on how dark you want it to be) I always use 2 Tablespoons.
Mix with your mixer.
It will be a little lumpy just mash the lumps with a fork. Continue mixing.
You will have nice fluffy fresh brown sugar.
So now you won't have to worry about your brown sugar getting hard or running out.