Ok...so I have to make a cake for a 4 year old girl. Her mother is diabetic. I want a buttercream they can both enjoy without Mom having to scrape the icing off. Any suggestions? Thanks!

Make a swiss meringue buttercream using xylitol instead of sugar. Xylitol has a lower GI than sugar.

http://www.domestifluff.com/2009/04/sugar-free-swiss-meringue-buttercream/

Don't worry about making it so her mother can eat it. And Xylitol is a laxative, it can give the child diarrhea. Diabetics manage their sugar/carb intake on their own. So unless the mother specifically asks you to change your recipe, don't do it. And it's not only the icing, diabetics also have to watch their carbohydrate intake too. So it's fine if she can't have any or has just a nibble. She knows or she wouldn't be ordering from you! :)

Good point crafty. I do know people react to xylitol differently, I didn't even think about that when I commented. 

@kramersl ‍ Yeah, different sugar substitutes can be good or bad. Depends on the person. I can handle regular sugar, but substitutes don't agree with me (especially aspartame). Need to be careful with some of them as well because of how the body processes it. When in doubt, check with the receiver! (it's how I found out I can't use buttermilk or even certain vinegars for a friend of mine) Good luck! :)

My son is type1 diabetic. When he eats cake he counts carbs out and takes insulin for it. HE does not use sugar substitute in baking. All sugar turns to carbs and thats what he has to count not the actual sugar.