Add all your ingredients ground beef, onion, and bell pepper, everything except for potatoes cheese and milk to your skillet and cook on medium heat till lightly brown.
Then add potatoes and cook over a low to medium heat for about 15 more minutes with the lid on stirring occasionally.
Then add milk right into the cast iron skillet you are cooking in and stir in evenly. Lay cheese across the top and cook in a 375-degree oven for 15 to 20 minutes. The cheese will be bubbly and will form a delicate crust on top of your 100 year old casserole.