I do a gingerbread muffin rather than make it as the square. I do it in a sugar-free and fat-free also. Sometimes I add chopped prunes, sometimes apricots, and other times plumped raisins. I have even dome it plain! It goes over well.
Edited to add that I posted my recipe in the recipes.
Gingerbread is traditional with lemon sauce http://americanfood.about.com/od/holidayclassics/r/gingerbread.htm http://www.tasteofhome.com/Recipes/Gingerbread-with-Lemon-Sauce-2
Molasses/Treacle is one of those heritage foods in this area and the USA in general. If I lived in the NE I might be tempted to make these into whoopie pies.
I remember one book that featured this product which was so volatile to make (Sorghum Molasses) but saved the lives of many pioneers who lacked sugar in their diet, was by Robert Morgan (fascinating historical fiction author from the Blue Ridge mountains) This Rock, Gap Creek, and The Truest Pleasure. He has stayed at an innmates on the forum here, I am so jealous! Fascinating writer. - sharing in case anyone is looking for a good read.
I am usually a "from-scratch" baker but there are days when I do not feel like pulling all the stuff out for afteroon goodies for arriving guests. I have had great luck with Tra der Joe 's Gingerbread mix. I substitue half milk, half OJ for the water and add a little crystallized ginger and orange zest for a nice bite. It always dissappears and goes great with hot mulled cider.