Hamburger Steak Skillet Casserole with Mashed Potato Topping
Hearty one-pan comfort food combining seasoned ground beef with mushrooms and onions in a rich French onion soup gravy, topped with creamy cheddar mashed potatoes and broiled until golden. Perfect for family dinners or cold weather meals when you want something filling and satisfying. The cast iron skillet creates a beautiful presentation while the combination of beef broth and French onion soup adds deeper flavor than typical hamburger casseroles.
Ingredients
- 1 tablespoon olive or vegetable oil
- 2 pounds lean ground beef
- 1 cup yellow onion, chopped
- 2 8-ounce packages cremini mushrooms, quartered
- 3 garlic cloves, minced
- 1 teaspoon salt
- ½ teaspoon black pepper
- ½ teaspoon dried thyme
- ¼ cup all-purpose flour
- 1 14.5-ounce can diced tomatoes, undrained
- 1 10.5-ounce can condensed French onion soup
- 1 cup beef broth
- 1 tablespoon fresh parsley, chopped
- 1 tablespoon red wine vinegar
- ¼ teaspoon garlic powder
- 3 pounds Yukon Gold potatoes
- 4 tablespoons butter, softened
- 1 cup milk, warmed
- 1 ½ cups sharp white cheddar cheese, shredded
- salt and pepper
Instructions
- 1
Heat oil in cast iron pan over medium-high heat
- 2
Add ground beef, onion, and mushrooms, breaking beef apart as it cooks until browned and vegetables are soft
- 3
Add garlic, salt, pepper, and thyme and cook 1 minute
- 4
Stir flour into mixture and cook 1 minute
- 5
Stir in tomatoes, condensed French onion soup, beef broth, parsley, vinegar, and garlic powder
- 6
Simmer for 10 minutes, stirring occasionally
- 7
Meanwhile, peel potatoes and cut into chunks, place in pot and cover with water
- 8
Add salt to water and bring to boil, simmer until potatoes are soft
- 9
Drain potatoes, add butter, milk, and cheese, mash until smooth and season with salt and pepper
- 10
Spread potatoes on top of beef mixture
- 11
Broil for 3 to 5 minutes
Tips
Use a 12-inch cast iron skillet for even heat distribution and attractive presentation from stovetop to oven.
Warm the milk before adding to potatoes to prevent cooling and ensure smooth, creamy mashed potatoes.
Watch carefully during broiling as the potato topping can brown quickly - 3-5 minutes is usually perfect.
Good to Know
Refrigerate leftovers for up to 3 days in covered container
Can assemble completely and refrigerate up to 1 day before broiling
Serve immediately while potato topping is golden and beef mixture is hot
Common Mistakes
Don't skip draining tomatoes or mixture will be watery
Avoid overmixing mashed potatoes or they become gluey
Don't broil too long or potato topping will burn
Substitutions
FAQ
Can I make this without a cast iron skillet?
Yes, use any oven-safe skillet or transfer the beef mixture to a baking dish before adding potatoes and broiling.
What if I don't have French onion soup?
Substitute with additional beef broth plus 1 packet onion soup mix, though flavor will be slightly different.
How long will leftovers keep?
Store covered in refrigerator for up to 3 days. Reheat individual portions in microwave or whole dish in 350F oven.