Just made up a batch of these this morning, and the house smells heavenly. This can be done in stages if you are busy: parboil the potatoes and set them aside for a few hours (or more). Brown the onions, and set them aside too. Eventually, put the whole thing together. You can also use different fillings, or toss in some sauteed 'shrooms, cooked kasha, or other seasonings. I have been told that these can be frozen, partly baked, and then baked for additional time after removal from the freezer. I haven't tried that (these don't last long around here), but would love to hear your experiences.