A friend asked me if I could make an egg & dairy free cake for her daughter...I found a Wacky Cake recipe which uses vinegar for eggs and oil for butter. I was going to try to make my own frosting swapping out the butter for all shortening and using non-dairy creamer instead of my normal whipping cream. Has anyone done this before? My kids are Tree Nut allergic so I've never had to take the egg or milk out of anything!! I checked the labels of all the ingredients and nothing says contains milk...the butter extract from Wilton had a wide variety of possible tumbling with peanuts, tree nuts etc (which surprised me) but I will not using anything but vanilla for this particular cake.
I make all-shortening buttercream all the time. I don't put any non-dairy creamer in it, but if you've checked the ingredients to make sure there's really no dairy in it, there shouldn't be any problem.
I haven't done baking without eggs but I have made cake dairy-free by using a soy margerine instead of the butter and rice milk. I made a SMBC frosting using the soy margerine instead of butter. I did substitute a couple tablespoons of vergetable shortening for the a couple of the margerine in the frosting because I wasn't sure what the texture of the margerine would be like. I don't think it was necessary though. The taste and texture worked well.