My favorite casserole! Got the recipe from Mom. Not sure where she found it. It seems like a lot of onions, but it's really yummy - unless you hate onions, I guess! I don't like mushrooms so I don't use them. Never tried using the green pepper rings either. The original recipe says to use either a 12 oz can of corn or a 10 oz package of frozen peas. I tried using peas once, but we didn't like it. If you'd like to use peas instead of corn, the recipe says to sprinkle them on top before adding the dumplings. Don't let them bake for 2 hours with the rest of the ingredients... Mom never made the dumplings with parsley or sage. I tried making the dumplings with sage and parsley once and didn't like it. And I hate to admit it, but I have no clue what salad oil is, so I use vegetable or olive oil.