Ok so I have to make a cake for a 4 year old girl whose mother is diabetic. I'm looking for a buttercream frosting they can both enjoy without Mom having to scrape the icing off the cake. Any suggestions? Thanks!
I've had good luck subbing out the sugar for a high quality sweetener alternative, such as xylitol or inulin (Just Like Sugar or a generic brand). If you use xylitol, it's best to use a brand that is made from non gmo Birch, to reduce the possibility of gastric distress. If you buy xylitol, you'll want to powder it with a tablespoon or so of resistant starch or cornstarch.
Erythritol (Truvia, Swerve) can work but it has a cooling effect, which leaves a minty feeling on the tongue. You can avoid this by using cream cheese, but that wouldn't be a true buttercream frosting.
You can also make a cooked buttercream (german, italian, etc) with any of the above sweeteners and they will come out nearly equal to cooked buttercreams made with sugar.
I would suggest checking with the diabetic woman before using the sugar substitutes. My DD is diabetic and there are some substitutes she used and some she couldn't. They all just didn't work for her. Also so many diabetics are on the insulin pump now, they often will have sugar on a few occasions and just adjust the pump to cover the higher amount of insulin needed.
Another thing is that it isn't just the sugar, it is the flour etc. in the cake itself that a diabetic needs to consider. All starches turn to sugar in the body. After being diabetic for a long period many of them have problems with gluten. Diabetics are careful about all that they eat and it is a complex diet, not just avoid sugar. Most of them have a lot of understanding on how their body reacts to all these foods, she will know what is best for her if you ask. JMHO