French Onion Gnocchi Casserole
This French Onion Gnocchi Casserole is a delectable fusion of Italian and French comfort classics in one cheesy and decadent dish. It is made of fluffy gnocchi covered in French-style caramelized onions tossed in rich béchamel sauce and topped with ooey-gooey mozzarella.
What is your definition of comfort food? For me, it is when you eat something that instantly makes you feel nostalgic and warm inside. It is like taking a bite full of happy, cozy memories! And when I am in need of instant food gratification, this French Onion Gnocchi Casserole always hits the spot. It has all the flavors of classic French onion soup and Italian gnocchi in one spectacular dish. It is perfect for those hectic weekdays or lazy Sundays when you crave a warm, hearty, yet effortless dish!
What is Gnocchi?
These soft and fluffy little nuggets of yumminess are a type of Italian dumplings traditionally made of flour, eggs, and potatoes. The dough is rolled and cut into small, bite-sized pieces, then pressed with a fork or any textured surface to create ridges. Just like pasta, these dumplings have a neutral, mild taste that takes on the flavor of the seasonings, herbs, and spices used to cook them. So, the ridges trap the sauce, making each bite flavorful!
The beauty of comfort food is that they are made of simple, everyday kitchen ingredients that allow you to make yummy, hearty dishes anytime the craving hits. Gnocchi might not be as common in a US kitchen, but once you have tried this recipe, I am sure you will be keeping a pack or two in your fridge moving forward!
- Gnocchi– I used pre-made gnocchi to make my life easier! But hey, if you prefer making your own, go ahead and do so. I usually buy Dellalo gnocchi because they are tender but not gummy and are unfailingly delicious. However, you can also try Trader Joe’s cauliflower gnocchi if you are looking for a healthier option!
- Yellow onions– are ideal for caramelizing because they have the perfect balance of sharpness and sweetness. You can also use white onions if that is what you already have.
- Mozzarella cheese- melts into gooey perfection as the casserole bakes! You can also use Gruyere, gouda, provolone, or any other type of swiss cheese.
- Salted butter– I used this to sauté the onions with. I love how it adds a richer flavor to the dish. You can use oil as a substitute, though.
- All-purpose flour– is used as a sauce thickener.
- Whole milk– makes the sauce super creamy!
- Granulated sugar– a bit of sweetness to round the flavors up nicely!
- Worcestershire– this seasoning adds a savory, salty, and umami flavor to the dish.
- Fresh thyme– adds an earthy, peppery, and soothing minty taste. Feel free to use other herbs like parsley or rosemary.
- Beef broth– Is used to deglaze the caramelized onions and give the sauce an extra boost of flavor.
- Salt and pepper to taste
How to Make French Onion Gnocchi Casserole:
It will only take less than 30 minutes to get the casserole ready for baking, then just let your oven do its magic! Easy, fuss-free cooking using wholesome ingredients- what more can you ask for?
- Preheat your oven to 400 degrees.
- Slice your onions thinly and evenly.
- Make the French Onion. In a large skillet, melt two tablespoons of butter over medium-high heat. Add the sliced onions and sauté for about 2 minutes or until they turn limp and lightly golden. Add the sugar, Worcestershire, and thyme, then season with salt and pepper.
- Deglaze. Continue cooking the onions for a minute or two, then pour in the beef broth. Scrape the bottom of the skillet and stir until well combined. Let it simmer using low heat for about 20 minutes or until the onions turn golden brown.
- Cook the Gnocchi. While the onions are simmering, cook the gnocchi according to package instructions. Once done, drain and place them in the baking dish.
- Make the roux. In a small saucepan, melt the remaining tablespoons of butter over medium heat. Add the flour and whisk for a minute or until a thick gravy forms. Pour in the milk and whisk until thickened, about five minutes. Add salt and pepper to taste.
- Assemble. Add the caramelized onions on top of the gnocchi evenly. Then, pour the white sauce to cover the onions. Sprinkle the shredded mozzarella all over.
- Bake. Place the casserole in the oven and bake for about 10 to 15 minutes or until the cheese has turned golden brown. Garnish with fresh thyme.
Tips for Making the French Onion Gnocchi Casserole:
- Cook the onions low and slow! Use low heat and let them simmer until their natural sugar is released and they turn a golden brown. Do not rush this by increasing the heat because you might overcook them.
- Do not overcook the onions. This will give the dish a bitter taste!
- Use a large skillet. This is to allow the onions space to cook and caramelize evenly and the broth to quickly sizzle and thicken.
- Use a wooden spatula to scrape the bottom of the skillet really well without damaging it. The browned bits of onions stuck on the pan as essential for the flavor development of the dish.
- Make sure to stir continuously when making the sauce, or you will run the risk of lumps forming.
- Use room temperature milk. Do not add cold milk to a hot pan because it will curdle, and the sauce will become grainy.
Serving and Storing
This French Onion Gnocchi Casserole can be served as a yummy side dish with your favorite holiday entrees like Herb Citrus Butter Roasted Turkey or Bacon & Cranberry Stuffed Pork Tenderloin. However, this carb-loving dish is hearty enough for lunch or dinner with crusty bread or green salad on the side.
If you have leftovers, place them in a lidded container, or cover your casserole with foil and place it in the fridge. It should be good for 2 to 3 days.
French Onion Gnocchi Casserole
- 1 pkg Gnocchi ( or roughly 2 cups)
- 5 tbsp Unsalted butter
- 3 tbsp All-purpose flour
- 1 1/2 cups Whole milk
- 1 large Yellow onion, sliced thinly
- 2 tsp Granulated sugar
- 1 tbsp Worcestershire
- 1 1/2 tsp Chopped fresh thyme + more for garnish
- 1/2 cup Beef broth
- 1 cup Shredded mozzarella
- Kosher salt and pepper to taste
- Preheat your oven to 400 degrees. Spray an 8X8 baking dish with non-stick cooking spray and set aside.
- In a large non-stick skillet melt 2 tbsp butter over medium-hight heat. Once melted, add the onions. Let the onions cook four about two minutes. Next, add in the granulated sugar, Worcestershire, thyme, salt and pepper. Stir and continue to cook for a few minutes.
- Pour in the beef broth into the skillet and start scraping the bottom of the skillet making sure everything is well combined and turn the heat to simmer.
- Stir the oninos to keep them from burning at the bottom of the skillet until golden brown; about 20 minutes. Once cooked, set aside.
- While the onions cook, bring a large pot full of water to a boil. Add the gnocchi and cook according to package instructions. Once the gnocchi has cooked, drain through a colander and add the cooked gnocchi to the prepared baking dish.
- In a medium saucepan, melt the remaning tbsp of butter over medium heat. Add in flour and whisk until a roux forms; about a minute. Pour in the milk and whisk until thickened about five minutes. Add in the salt and pepper to taste.
- To assemble the casserole, evenly place the onions over the gnocchi. Next, pour the white sauce over the onions followed by the mozzarella. Bake for about 10 to 15 minutes or until cheese has turned golden brown. Garnish with fresh thyme.
This is my kind of casserole, love it!
You can’t beat white gravy!!
i always wondered how to spell tookus. 🙂
Ha!! I think tookus is the right way:)
Holy Cow! This was so good! And so easy. Followed the recipe as written and it came out fantastic. Loved it.
Yay!! I am so glad you enjoyed the recipe!
Only you could make me SO hungry after already eating a huge meal! This is OUT of this world amazing girl!!
I can’t tell you how wonderful this looks to me right now. Total and complete comfort.
All hail the giant ass casserole!! 🙂
I want this to get me through winter! All that cheese and coziness – yasssss!
What perfect comfort food! This looks incredible!
Thanks so much, Jessica!
Can this be made ahead of time, like 24 hours? And obv refrigerated.
Yes! Absolutely, Heidi!
Won’t the gnocchi get tough if you reheat?
Hmmm….good point. Could make the filling ahead of time and then day you want to make the casserole just reheat the filling on the stove stop, boil the gnocchi, assemble, and then bake? That way the gnocchi won’t be soggy. Sorry about that!
I forgot to tell you earlier…made this for Christmas Eve. Major hit. It was so delicious! Definitely rich but absolutely delicious.
Yay!!! I am thrilled you liked the recipe:)
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Made it this morn. It’s okay. I think next time I will whisk the onion mixture in with the white sauce. The onion mixture was a bit overpowering with the Worcestershire. I did brown the gnocchia in butter after boiling and before placing in the dish. I think this dish would freeze and thaw well with a gentle warm up in the micro. I’m going to try chicken stock instead next time too see if that will help cut the bitterness. It is such a beautiful dish, and I wanted to really rave about it. I’m going to give it another go, but just tweak it a bit. Lovely writing by the way.
Hey Lane! Definitely let me know if you tweak the recipe with chicken stock. Would love to know how it tastes! Thanks!
Oh my word! This was delicious! I caramelized the onions in a cast iron skillet. After scraping them out I used the same skillet (with some of the ooey gooey goodness still there from the onions) to make the sauce. Fantastic! The only substitution I made was veggie broth instead of beef, as it’s what I had on hand. This recipe is a keeper and will definitely be on the regular rotation. Thanks for a such a great recipe!
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Looks amazing. What size casserole did you use?
Hey Dave! You can use a 9X13 or 8X8. Thanks!
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I made this for a bunch of my firefighters. The only hook was my phone died & I had to kind of wing it. I sautéed the onions & boiled the gnocchi per the recipe and then I pored the beef broth into the onions with Worcester but we only had a little in the bottle so I used really good balsamic. I forgot the sugar but the balsamic covered for me. I also forgot the milk and put the flour directly into the both that was at a rolling simmer (I’m not sure there is such a thing as a rolling simmer but I’m used to improvising). I also added sliced fresh mushrooms as I try to get these guys to eat as many veggies at once as I can. The bottom line is this turned out amazing! I paired it with a Cesar salad (more veg) and sweet tea. Holy moly, no leftovers.
Hey Mike!! Um, you need to have your own cooking show! Way to improvise!! So glad you enjoyed the recipe!!
Yes, total kick-ass! I loved it but my man struggled with the sweetness of the onions so I am going to try again with just 1 tsp sugar. Any ramifications?
You can 100% caramelize onions without adding any sugar. Sauté them low and slow and the onions all by themselves will cook into a jelly. It’s amazing. Adding sugar is the shortcut.
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Best gnocchi dish we’ve ever had! Like rustic french onion soup giving you a big hug.
This is AMAZING!!!! I substituted the mozzarella with smoked Gruyère cheese 💕. Sweetness is incredibly balanced! Thank you!!
Yay!! I am so happy that enjoyed the recipe!
I think this recipe it one of the best I’ve ever made. It is the first time I have ever left a reply.
Literally the best comment ever!! Thank you so much!
Do you have the nutritional values for this recipe? I can’t find them.
Does this casserole reheat well in the microwave or oven after a day or 2 in the fridge?