Turns out, brown sugar has molasses added, and it is that molasses which has just dried out, and needs to be re-hydrated. (Fun fact! Dark brown sugar just has more molasses than light brown sugar.)
So, all you have to do is put some moisture back in. My favorite way has always been add water and microwave for 30-60 seconds. Sure, this makes brown sugar soup more often than not, but you were just making chocolate chip cookies anyways, right?
If soup isn't your thing, here are some other tips:
Here's what the brown sugar BAG says what to do:
- Place your brown sugar rocks into a microwave safe conatiner
- Wet a paper towel and place over the container
- Stretch a piece of plastic wrap on top of the paper towel
- Microwave for 30-45 seconds, check the sugar, microwave for an additional 30-45 seconds & check again.
- Chisel your rocks into tiny pieces and put in a sealed bag with a piece of bread. (Really) Next day or two, it should be all soft and ready to go
- Buy one of these oval clay tablets that are especially made to keep brown sugar soft always and forever. (You can buy them at any kitchen shop)
- Nuke it.
- Keep it in the fridge.
- Keep it in the freezer.