1015 Onion Casserole

This sweet onion 1015 Casserole is the best recipe when you’re jonesing for a sweet taste of home – if you’re from the south, that is! No matter where you are, however, from California all the way to New York City, Sweet Onion Casserole will transport all my onion lovers out there directly to Texas.

scoop of 1015 casserole coming out of a white dish

1015 Sweet Onion Casserole Recipe 

Originally, the 1015 onion was called the sweetest in the world after being discovered by Texas A&M horticulture professor, Dr. Leonard Pike.

He was a scientist for the Texas Agricultural Experiment College Station, and we have him to thank for this Texas onion casserole.

This main dish is for all the onion lovers out there because it’s an easy casserole with a simple recipe for those busy weeknights. It doesn’t take a long time to prepare, but it’ll be gone before you know it.

I love sweet onions so much I used them in my French Onion Chicken Casserole!

overhead picture of ingredients for onion casserole on a marble backdrop

Ingredients Needed

  • Large sweet onions – Vidalia onions or yellow onions are the best.
  • Swiss cheese – Cheddar cheese is a great substitute.
  • Saltine crackers – Substitute Ritz or other buttery cracker or traditional bread crumbs.
  • Eggs – Use large eggs at room temperature.
  • Evaporated milk- Use heavy cream of half & half as a substitute
  • Pantry Staples – Unsalted butter, salt, and black pepper.

How To Make 1015 Casserole

  1. Preheat oven to 350 F. Chop large onions into thin slices (around ½ inch slices).
  2. In a large skillet, melt butter over medium-high heat. Add onion slices to the skillet and stir. Saute onions until tender.
  3. In a prepared baking dish, place half of onions. Top with half the Swiss cheese and 3/4 cup of the cracker crumbs.
  4. Layer with the remaining half of chopped onions and top with the remainder from your cup of the cheese.
  1. In a small bowl, combine eggs, milk, and seasonings. Pour over cooked onions.
  2. Grab melted butter and mix with the remainder of the cup of cracker crumbs. Spread over top of casserole. 
  3. Bake in the preheated oven for a total time of 20 – 25 minutes or until golden brown on top. 

For the full recipe and detailed baking instructions, please see the recipe card at the end of this post.

baked 1015 casserole in a white dish with blue checkered napkin

What do I serve with 1015 Casserole?

This southern sweet onion casserole is best served with a simple side dish like sweet potatoes or a baked potato with sour cream and chives.

If you want to lighten it up, a fresh chopped salad with homemade Italian dressing is great!

How long does it last?

This casserole will last in the fridge for up to 3 days, as long as it’s placed in an airtight container. When reheating, if it seems dry, add in a little chicken broth to rehydrate.

Can I make this ahead of time?

Yes, this is a great casserole to make ahead of time. Cook your onions as directed, before placing them in a covered casserole dish and putting it in the fridge.

The cracker topping is easy to make ahead of time and stored in a plastic bag until it’s time to make your casserole.

When you’re ready, just assemble according to the instructions and enjoy.

dish of 1015 casserole with a scoop missing

Best Casserole Tips

  • It’s easier to cut the onion in half and then slice. But you can slice them into whole onion rings if you like.
  • Make sure to spray your casserole dish with a nonstick spray, whether that be PAM cooking spray or a healthier olive oil spray to prevent sticking.
  • If you want maximum crunch for your topping, try crushing up potato chips in a medium bowl before coating the top if your casserole.
  • For all my cheese lovers out there, you can also add in parmesan cheese mixed with a tablespoon butter to the topping to create a more cheesy topping.
  • To cut your onions without crying, try putting wet paper towels next to you to absorb the acid that the onions release. Another trick is to freeze or chill your onions, rather than cutting them at room temperature.
  • Add in a pinch of brown sugar and a dash of soy sauce for a richer flavor.

If you love this recipe as much as I do, pin this to your favorite casserole Pinterest board and share it on your favorite social media channels!

casserole with scoop missing and blue banner with text "sweet onion 1015 casserole"

This sweet onion 1015 casserole is a staple in Texas, and is about to become a staple in your home as well, no matter where in the world you are. Not only is it easy to make but it brings that comfort food feel to your dinner table, and pairs well with a number of side dishes.

Yield: 9 servings

1015 Casserole

overhead picture of 1015 casserole in square white dish

This sweet onion 1015 Casserole is full of tangy Swiss cheese, sweet 1015 onions, and layers of buttery crackers, baked to perfection!

Prep Time 10 minutes
Cook Time 25 minutes
Total Time 35 minutes

Ingredients

  • ¼ cup unsalted butter
  • 3 large sweet onions, peeled and sliced
  • 2 cups shredded Swiss cheese, divided
  • 1 ½ cups crushed saltine crackers, divided
  • 2 large eggs, room temperature
  • ¼ cup evaporated milk
  • 1 teaspoon salt
  • ½ teaspoon pepper
  • 3 tablespoons unsalted butter

Instructions

    1. Preheat oven to 350F.
    2. In a large skillet, saute the onions in the ¼ cup butter over medium heat until tender.
    3. Layer ½ the onion mixture in bottom of a 8x8 baking pan.
    4. Cover with 1 cup Swiss cheese.
    5. Top with 3/4 cup saltine crumbs.
    6. Add remaining onions in a layer and top with remaining cheese.
    7. In a bowl, combine the eggs, milk, and seasonings.
    8. Pour over onion layers.
    9. Melt 3 tablespoons butter and mix with remaining cracker crumbs.
    10. Spread over top of casserole.
    11. Bake at 350F for 20-25 minutes or until bubbly and the topping is golden brown.

Notes

  • It's easier to cut the onion in half and then slice. But you can slice them into whole onion rings if you like.
  • Make sure to spray your casserole dish with a nonstick spray, whether that be PAM cooking spray or a healthier olive oil spray to prevent sticking.
  • If you want maximum crunch for your topping, try crushing up potato chips in a medium bowl before coating the top if your casserole.
  • For all my cheese lovers out there, you can also add in parmesan cheese mixed with a tablespoon butter to the topping to create a more cheesy topping.
  • To cut your onions without crying, try putting wet paper towels next to you to absorb the acid that the onions release. Another trick is to freeze or chill your onions, rather than cutting them at room temperature.
  • Add in a pinch of brown sugar and a dash of soy sauce for a richer flavor.
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    Nutrition Information:

    Yield:

    9

    Serving Size:

    1

    Amount Per Serving: Calories: 271Total Fat: 18gSaturated Fat: 11gTrans Fat: 0gUnsaturated Fat: 6gCholesterol: 89mgSodium: 375mgCarbohydrates: 18gFiber: 1gSugar: 7gProtein: 10g

    This nutrition information was generated via a third party, Nutritionix, and we can not be held liable for any discrepancies in the information provided.

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    3 Comments

    1. Mindy says:

      SO delicious! We love it and will be making this again

    2. My daughter who is an onion LOVER, devoured this dish. Will be making it again.

    3. Michaela Kenkel says:

      OMG!! We LOVED this casserole! A friend told me about your website and I have so many recipes printed already. Casseroles are my favorite comfort food and we just got a new favorite with this one!

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