Brown sugar adds flavor to desserts and baked goods. It can be substituted for maple sugar, and maple sugar can be substituted for it in recipes. Brown sugar caramelizes much more readily than refined sugar, and this effect can be used to make glazes and gravies brown while cooking.
For domestic purposes one can create the exact equivalent of brown sugar by mixing white sugar with molasses. Suitable proportions are about one tablespoon of molasses to each cup of sugar (one-sixteenth of the total volume). Molasses comprises 10% of brown sugar’s total weight, which is about one ninth of the white sugar weight. Due to varying qualities and colors of molasses products, for lighter or darker sugar, reduce or increase its proportion according to taste.
In following a modern recipe that specifies “brown sugar”, one usually may assume that the intended meaning is light brown sugar, but which one prefers is largely a matter of taste. Even in recipes such as cakes, where the moisture content might be critical, the amount of water involved is too small to matter. More importantly, adding dark brown sugar or molasses will impart a stronger flavor, with more of a suggestion of caramel.
Brown sugar that has hardened can be made soft again by adding a new source of moisture for the molasses, or by heating and remelting the molasses. Storing brown sugar in a freezer will prevent moisture from escaping and molasses from crystallizing, allowing for a much longer shelf life.