Let boil until liquid is reduced by half, approximately 10 to 15 minutes, which allows the natural sugars to come out of the barley.
The remaining liquid should be brown.
Drain the barley, saving the liquid, and either eat the cooked barley or throw away (it's only 2 tablespoons).
Return the liquid to the pot and add up to 2 tablespoon sugar, or other sweetner of choice.
Simmer the liquid for about 15 minutes.
If you want, at the end of simmering for 15 minutes, add up to 2 tablespoons lemon juice (although, for me personally, adding lemon juice would just get in the way of the barley flavor).