The potatoes and nuts make this a really creamy sauce, without using any real or fake cheese. The carrots give it a nice orange color....
If you don't have mayo, you can use oil (I like olive oil for this). It's pretty good, but it's not mayo....
I use a basic crust for practically all my recipes. You can find the recipe for it on my apple pie recipe....
If you can't find a vegan version, make your own....