This easy dump-and-go Traeger Steak and Potato French Onion Casserole is a hearty meat-and-potatoes main course that comes together in minutes and feeds a crowd. Use thinly sliced steak from the meat counter or repurpose leftover steak or pot roast for a frugal, flavorful meal.
Traeger French Onion Casserole with Beef
I love simple weeknight dinners that are quick to assemble but still taste incredible. This casserole checks both boxes. It was inspired by a French onion potato side, but I turned it into a full meal by layering on shaved beef. Serve it with a crisp green salad and grilled vegetables for a complete dinner everyone will enjoy.
Pair with a Greek-style salad or grilled zucchini or asparagus for a balanced plate. The casserole is flexible — swap cheeses, use homemade French onion soup, or adjust seasoning to your taste.
Discover more Traeger beef recipes and hearty casseroles to expand your menu.
Recipe Shopping List
You may already have most of these on hand. Quantities and full instructions are in the recipe card below.
- Condensed French onion soup (canned)
- Beefy onion dry soup mix
- Butter
- Frozen diced potatoes with onion (Simply Potatoes or similar)
- Thinly sliced or shaved ribeye (or leftover steak)
- Garlic salt (or garlic powder + salt)
- Mozzarella cheese, shredded
- Swiss cheese slices
This casserole adapts well to other French onion recipes and variations.
How to Make This Recipe
Below is a concise overview of the process to give you a sense of what’s involved. Follow the full recipe card for exact measurements and timing.
- Preheat and prep: Heat your pellet grill or oven to 325°F. Lightly spray a large 9×13 or high-sided baking dish with cooking spray. Mix the condensed French onion soup, dry onion soup mix, and melted butter — set aside.
- Assemble: Spread the diced potatoes in the pan, sprinkle with shredded mozzarella, then layer the sliced steak on top. Season the meat with garlic salt or your preferred seasoning.
- Top and pour: Pour the soup-and-butter mixture evenly over the potatoes and steak so everything is coated.
- Cook: Bake in the pellet grill or oven for 25–30 minutes, until the potatoes are tender and the beef is heated through. During the last 5–10 minutes, layer Swiss cheese slices over the meat and warm until melted.
- Serve: Let the casserole rest briefly, then serve hot with crusty bread and fresh vegetables or salad.
This dish pairs nicely with smoked French onion soup or a simple green salad.
Recipe FAQ
Cover the baking dish or transfer leftovers to an airtight container and refrigerate. They’ll keep for 3–4 days.
Reheat individual portions in the microwave, or warm the casserole in a 350°F oven until heated through. An air fryer or instant pot on a low reheat setting also works for single servings.
Yes. Homemade French onion soup or a prepared onion soup base can be used — the dish will still be rich and flavorful.
For more French onion inspired dishes, try risotto or stuffed meatballs.
More Meat & Potatoes Recipes
- Loaded Potato Skins
- Loaded Baked Potatoes
- Steak and Potato Pie
- Beef Stew
- Smoked Balsamic Pot Roast
- Surf and Turf Seafood Feast
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Traeger Steak and Potato French Onion Casserole
Simple, satisfying, and adaptable — this steak and potato French onion casserole is perfect for a pellet grill or the oven when you want a comforting, all-in-one meal.
15 minutes
45 minutes
1 hour
Ingredients
- 2 (10-ounce) cans condensed French onion soup
- 1 envelope Beefy Onion dry onion soup mix
- ½ cup butter, melted
- 2 (20-ounce) bags diced potatoes with onions
- 1 pound thinly sliced ribeye (or shaved steak)
- 1 teaspoon garlic salt (or ½ teaspoon garlic powder + ½ teaspoon salt)
- 2 cups shredded mozzarella cheese
- 10 slices Swiss cheese
Instructions
- Preheat your pellet grill or oven to 325°F.
- In a bowl, combine the condensed French onion soup, beefy onion dry mix, and melted butter.
- Prepare a large, high-sided baking dish with cooking spray. Spread the diced potatoes evenly in the pan.
- Sprinkle the mozzarella over the potatoes.
- Layer the shaved ribeye on top of the potatoes and season with garlic salt.
- Pour the soup-and-butter mixture over the meat and potatoes. Bake for 25–30 minutes, or until the potatoes are tender and the meat is heated through.
- Place Swiss cheese slices on top during the last 5 minutes of cooking to melt.
- Serve hot with crusty bread and fresh vegetables or a green salad.
Notes
Use the canned condensed soup as-is — no need to prepare it before adding to the recipe. The canned soup helps create a rich, savory sauce as it cooks.
Nutrition Information:
Yield: 12
Serving Size: 1
Amount Per Serving:
Calories: 376Total Fat: 28gSaturated Fat: 15gTrans Fat: 1gUnsaturated Fat: 11gCholesterol: 87mgSodium: 517mgCarbohydrates: 8gFiber: 0gSugar: 2gProtein: 22g
Nutrition data provided here is an estimate.
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