Dairy & Refined Sugar Free Version?

It is basically a bread pudding recipe, based on the ingredients typically used in making french toast. You could substitute several different types of non-dairy milks, and sweetener of your choice. The recipe does direct you to cut the bread into squares, but you could slice it into 1 inch thick slices as well. I do not use margarine, or a "vegan" butter, so I have no experience with that in a baked product. However I would assume a fat is a fat- in the way it works within the recipe. I suspect that if you use both coconut milk and coconut suger, you are going to alter the taste profile in favor of coconut. It will probably taste quite good, but not be the same French toast flavor profile I know. But if it suits you, that's all that counts in the end.

I think it would be worth a try - with a dairy free, sugar free bread, instead of challah.