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Traeger Steak and Potato French Onion Casserole

This simple dump-and-go Traeger Steak and Potato French Onion Casserole is a “stick to your ribs” meat and potatoes main dish that takes minutes to throw together, and can feed an army-sized family. Buy some thinly sliced steak from your local meat counter, or use up some leftover steak or pot roast.

Traeger French Onion Casserole with Beef

I love super easy dinners that you can throw together quickly, but still taste awesome. This one definitely fits the bill. This recipe was inspired by the amazing Mandy from the South Your Mouth blog, and this French Onion Potatoes recipe.

I wanted to turn this from a side dish into a meal, and layering on some shaved beef was the perfect addition. Throw in a green salad like my Greek Salad and some grilled zucchini or asparagus, and you’re set!

Get more Traeger Beef Recipes here!

Steak & Potato French Onion Casserole shopping list

Wondering if you have to hit the store? Here’s the list of items you’ll need to make this recipe. For specific amounts, please refer to the printable recipe card at the bottom of the post.

  • Condensed French Onion Soup
  • Beefy Onion Soup Mix
  • Butter
  • Simply Potatoes Diced Potatoes with Onion
  • Sliced/Shaved Ribeye
  • Garlic Salt
  • Mozzarella Cheese
  • Swiss Cheese

Try my French Onion Stuffed Meatballs too!

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How to make Traeger French Onion Casserole

This is just the overview so you can see what you’re actually getting into here. When you are cooking, you’ll want to use the full recipe at the bottom of the page.


Preheat and prep

350° is where we want the grill. Prep a large 9×13 baking dish with cooking spray. Combine the soups, dry soup mix, and the melted butter. Set aside.



First potatoes, next mozzarella cheese. Then the sliced steak, and finally pour over all that soupy sauce you just made. Now sprinkle the steak with the seasoning.



Put it in the grill and cook for 25-30 minutes, or until the steak and potatoes are cooked. Layer on the swiss cheese slices on top of the steak during the last 5-10 minutes of cooking, and cook until melty.



Serve hot with some crusty bread, salad, and your choice of vegetables.

We make a great Smoked French Onion Soup too!

French Onion Beef and Potato Casserole FAQ

How do you store leftovers?

Cover the baking dish and stick it in the fridge. Easy peasy!

What’s the best way to reheat leftovers?

This one is fine for the microwave. Or you can toss it in the oven, air fryer, or instant pot if you want to heat up a single serving.

Are there any substitutions for canned soup?

Sure! You can make this with homemade french onion soup if you’d like.

Don’t miss our French Onion Risotto Recipe

More great recipes featuring meat and potatoes

Yield: 12 servings

Traeger Steak and Potato French Onion Casserole

Traeger Steak and Potato French Onion Casserole

Our simple Steak and Potato French Onion casserole is the ultimate meat-and-potatoes experience. If you don't have a pellet grill you can toss it in the oven!

Prep Time 15 minutes
Cook Time 45 minutes
Total Time 1 hour


  • 2 10-ounce cans French onion soup
  • 1 envelope Beefy Onion dry onion soup mix
  • 1/2 cup butter, melted
  • 2 - 20 ounce bags Simply Potatoes diced potatoes with onions
  • 1 pound thinly sliced Ribeye (I buy mine at Costco)
  • 1 teaspoon garlic salt (or 1/2 teaspoon garlic powder + 1/2 teaspoon salt)
  • 2 cups shredded mozzarella cheese
  • 10 slices swiss cheese


  1. Preheat your pellet grill to 325°.
  2. Combine the French Onion Soup, Beefy Onion dry mix, and the melted butter.
  3. Prep a large, high-sided rectangular baking dish with cooking spray. Put the potatoes in the pan.
  4. Sprinkle the mozzarella cheese on top of the potatoes.
  5. Layer the shaved ribeye on top of the potatoes. Sprinkle with the garlic salt.
  6. Pour the combined butter + French Onion mixture into the pan all over the meat and potatoes. Put the baking dish in the pellet grill (or oven, if you don't have a pellet grill). Bake for 25-30 minutes, or until the potatoes and meat are fully cooked.
  7. Layer on the swiss cheese on top of the meat during the last 5 minutes of cook time.
  8. Serve hot with some crusty bread and fresh vegetables.


Don't prepare the condensed soup before using. It is perfect just the way it is.

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Nutrition Information:



Serving Size:


Amount Per Serving: Calories: 376Total Fat: 28gSaturated Fat: 15gTrans Fat: 1gUnsaturated Fat: 11gCholesterol: 87mgSodium: 517mgCarbohydrates: 8gFiber: 0gSugar: 2gProtein: 22g

Nutrition data provided here is only an estimate.

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Nicole Johnson

Nicole Johnson, a self-taught expert in grilling and outdoor cooking, launched Or Whatever You Do in 2010. Her blog, renowned for its comprehensive and creative outdoor cooking recipes, has garnered a vast audience of millions. Nicole's hands-on experience and passion for grilling shine through her work. Her husband, Jeremiah Johnson, also plays a pivotal role in recipe development, adding his culinary flair to the mix. Together, they form a dynamic duo, offering a rich and varied outdoor cooking experience to their followers.


Wednesday 8th of June 2022

Is the ribeye already cooked?


Friday 10th of June 2022

@Nicole Johnson, Thanks, one more thing, does it come packaged or do I need to work with the Costco butcher?

Nicole Johnson

Wednesday 8th of June 2022

Nope! It is thinly shaved ribeye and cooks along with the potatoes and sauce.

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