Substitute 1 cup of dark brown sugar plus 2 teaspoons of molasses for an equivalent amount of palm sugar, as the molasses adds a deep flavor similar to that of palm sugar. Another option is to substitute plain brown sugar, though its flavor is not as strong.
Palm sugar is sometimes confused with coconut sugar, though they are not the same; palm sugar is actually from sugar palm instead of the coconut palm. Both can be found in specialty markets. Palm sugar may be solid and crumbly or thick and gooey; it depends on how long it is processed before shipping. Substituting maple sugar or date sugar for palm sugar also works.