I've always made muffins without any sugar, they are sweetened with dried and fresh fruits and veggies (carrot, sweet potato) but there are also more savoury muffin recipes you could try. I always felt that although dried fruits are still high sugar/sweetness it wasn't the same as cane sugar and there are nutritional benefits in various dried fruits which you don't get with sugar. Even if you did add some sugar or honey as pp said it is still going to be less than shop bought cakes/candies etc.
There's a recipe for chickpea cupcakes which is pretty good. I offered them to a bunch of adults along with DS and not one of them knew they were eating basically beans and eggs. There's another for red kidney bean choc cup cakes which tbh I wasn't keen on but my DS thinks they are great. I have to be careful how many he has as beans seem to make his poo pretty lose.
Also you can frost muffins or cup cakes with cream cheese rather than icing or butter icing.
I like ana's popsicle idea. We made a dozen ice pops, half banana whizzed with milk and blueberries, poured out several full ice pops then several more just half full. Other half banana whizzed with milk and raspberries, again poured out several full pops and topped up the half blueberry pops to make a two-tone pop. DS went crazy for them!
