Katy, I use all of of those ingredients but I also add carrot and celery, I use my old food processor that I use to.chop the onion so they are not quite grated but . very finely chopped. Umm, I use continental beef stock, tomato sauce, thyme or mixed herbs and throw in frozen peas towards the end. I cook that earlier in the day and add the mashed potato once its cooled a bit. I put grated cheese and pepper on top then bake. Its basic but works.
