Wow, torbetta, that recipe sounds really complicated! The way I make scalloped spuds might be a little easier -- try this and see what you think:
Use olive oil or safflower oil instead of the butter. Put it in a large glass baking pan with a teaspoon or so of minced garlic. Slice a layer of unpeeled potatoes into the pan, then sprinkle them generously with salt and pepper and cilantro and sprinkle them VERY generously with flour. Now add a layer of sliced onions; you should have about the same amount of onions as what you've got potatoes. (Optional: add a thin layer of grated cheese here if you want cheese, and add meat here if you want.) Repeat the layers of potato, salt, pepper, flour, and onion. Now pour the soy milk over the potatoes, till it comes halfway up the depth of the pan. Sprinkle the top with paprika and bake at 375 till bubbly and browned.
Apologies in advance to those who have to measure -- I can't.