How to use sugar substitutes in baking recipes but avoid the dryness.

BetteIrene Love your thorough answer.

First, don't try to develop recipes of your own right now--get a little practice and a feel for working with substitutes by following recipes that have been developed by someone who can afford to mess around with ingredients.

Sugars are hygroscopic, which allows baked goods to pull moisture and humidity out of the air so they will be moist and fresh and will stay that way longer.

Not only that, refined sugars add structure, texture, and volume to cookies, cakes, meringues, and other baked goods. Sugars are what makes food (including meat and vegetables) turn golden brown and delicious through caramelization. Sugar also helps thicken jams and pie fillings, yeast will starve without it, and it helps tenderize baked goods.

The test kitchens at Better Homes and Gardens baked white cakes using sugar, aspartame, saccharin, etc. To see the differences in the results, go here:
http://www.diabeticlivingonline.com/diabetic-recipes/sugar-substitute/baking-with-sugar-substitutes/

Back when I was baking at a cafe, customers were constantly imploring me to bake something decadent (or at least edible) with fake sugar. I've done dozens of searches and baked a few recipes that seemed promising; I've sampled dozens of finished products offered at trade shows or baked by friends and co-workers. I have come to this conclusion: If it was possible, Nabisco or Pepperidge Farm would have already done it.

I had the best luck with recipes put out by the American Diabetes Association.
http://google.diabetes.org/search?site=Diabetes&client=default_frontend&proxystylesheet=recipe_frontend&ie=UTF-8&sort=date%3AD%3AL%3Ad1&entqr=3&oe=UTF-8&ud=1&output=xml_no_dtd&requiredfields=main_ingredient%3A.course%3Adessert&getfields=meta_title.description&filter=p&q=&main_ingredient=Main+Ingredient&course=dessert

I have added applesauce to replace some of the oil/butter in recipes, and sour cream as the 'wet' (along with eggs) source to a cake, but never used them as a substitute for sugar or a sweetener. I know that agave can be used as a substitute for sugar, and that there is information on substituions on the bottle I have at home (but I'm not at home right now, I'm in the U.K.!). Being that its liquid, you could probably also use maple syrup (depending on the flavor outcome you desire) or honey. If you are baking a spice cookie or muffin/quick bread molasses might also help.