You can use cream of mushroom soup but I actually prefer the cream of chicken soup. You can use canned chicken broth in lieu of the water. I haven't tried using canned beef broth yet with cream of mushroom soup but it sounds like a good idea now. YEARS ago, when I was trim & young, I found the original recipe in the magazine our electric company sends out, recipes from the readers. I winged it and made it mine. As I am not particular about how many potatoes or how small or large the onion. Or precise with the hamburger. This is one of my favorite recipes, hope to be yours too.
Preheat oven to 350 degrees F. Cook the ground beef fully. I like to use a big chicken cast iron fryer for this as it can go into the oven when I am ready. Drain off the hamburger & if desired do this in a colander and run hot tap water over it all to remove extra grease.
Add the cooked hamburger back into the skillet or in the casserole dish of choice. Add the cut up potatoes, then the chopped onion. Then top with the peas.
Add the soup and the water together. Pour this all over the casserole. Cover with aluminum foil. Takes about an hour to bake at 350 degrees F, but you are waiting on the potatoes and onions to be done & this dish to look nice, hot, & bubbly.
I am fine with this recipe as is, and have had it to be like a nice gravy on all, much better to let sit at room temperature 30 or so minutes so it melds. But has came to my attention that maybe others might want some more flavors going on. Inspired by other recipes I would say that I would even attempt to add a pack of DRY ONION SOUP MIX to this to see how that works. Onion & peas are a nice combo any way, so not sure how that could fail. Maybe in lieu of one can of the water, add a nice can of beef broth or consume? Any other suggestions are & will be welcomed. As I never would have considered onion soup mix had someone else found it just lacking in taste to them.