Pre-heat oven to 375°F.
In an iron skillet, over medium heat, add ground beef, onion and bell pepper; mix well and cook until lightly browned.
Add potatoes; cover with a lid; reduce heat to low to medium; cook for 15 minutes; stirring occasionally.
Add milk and corn starch to the iron skillet; stir until completely combined; season with salt and pepper.
Place cheese on top of the casserole.
Place in pre-heated oven and bake for 15 to 20 minutes or until the cheese becomes bubbly and forms a delicate crust on top.
Remove from oven and serve warm.
