This is so important. Molasses can vary in sweetness, consistency, and ingredients. For this recipe you need mild unsulphured molasses. Unsulphured molasses is sweeter and doesn't contain preservatives, and comes in mild, dark, and blackstrap varieties. I prefer mild unsulphured molasses for baking because it offers less bitterness, so for this recipe I recommend Grandma's Original Molasses or something similar.