Cutting into a baked onion, only to find it full of caramelized onion is a magical thing! These french onion stuffed onions deliver on that amazing promise. It’s like a bowl of thick french onion soup, but the bowl is just more onion! I loaded these stuffed onions with tons of bread and cheese on top, and when they come out of the oven piping hot and dripping with melted cheese it’s a special moment.
The inspiration for this recipe
When I posted about these ropa vieja stuffed onions, someone mentioned it might be cool to do them with french onion soup. I jumped at the idea at first, but then became somewhat skeptical. Won’t the soup drip out of the onion when it bakes? I decided to try it anyways and just make the soup super thick! It worked out great and these onions were an epically comforting dinner.
Preparing the onions
If I was filling these with something a little more thick, I wouldn’t need to be as careful about prepping them, but since we are dealing with soup, you need to make sure there are no holes at all in the onion. Start by cutting off about 1/4 of the top, then flip it over and slice off the roots at the bottom. Peel off any skin like layers, then make slices in the inner layers, leaving the last two layers intact. Use a sharp spoon if you have one, or just any spoon, and cut out the inner layers, being careful not to make any holes.
You need a lot of onion for this recipe, so it’s ok if you mess up. I messed up twice. As you can see in the photo below, I left more layers closer to the bottom of the onion. When you try and clean those out, it can pull the base of the onion inward and create a small hole. I filled the onions up with water when I finished to make sure they didn’t have any leaks!
Making the french onion filling
Once you have two solid onion “bowls”, chop up all the insides of the onions, plus the remaining onions. Cook it with some butter for about 45 minutes until it is caramelized and delicious!
Add some thyme, garlic, and butter. Then add a little flour (photo above) then broth. Much less broth than if you were making onion soup. You want it thick!
Stuffing the onions with the french onion mixture
Put the hollowed out onions in a baking dish and add the soupy goodness! I baked these for about 35 minutes.
Add the cheese to the french onion stuffed onions
First the toasted cubes of bread, then the cheese! So much cheese. Broil these until the cheese is totally melted and starting to brown.
They come out of the oven looking amazing!
Serving the French Onion Stuffed Onions
I just put mine on top of rice. You could serve them just as-is. They would also be great with mashed potatoes.
Twists on this recipe
I like to mix up the onions sometimes and use a variety. You could also add worcestershire, sherry or white wine if you wanted. Serving this on the side of a perfectly cooked ribeye steak would be amazing.
Looking for a classic french onion soup recipe? I like this one.
For more fun twists on french onion soup, check out my french onion soup dumplings.
French Onion Stuffed Onion
- 6 large yellow onions
- 2 tablespoons butter
- salt and pepper
- 2 cloves garlic
- 1 teaspoon fresh thyme
- 1 tablespoon butter
- 2 tablespoons flour
- 1 1/2 cups beef broth
- 2 large sourdough slices
- 1 cup grated gruyere cheese
Prep the onions
- Start by trying to make the onions you will be using as a vessel because if you mess up, you have more onions to try with. Use the photos as a guide. Slice off about 1/4 of the top, then go to the bottom and slice only the roots off. Remove any layers that seem skin-like.
- Make slashes with your knife in a star shape at the open top of the onion, making sure not to cut the outer two layers. Any spoon will work but if you have a sharp spoon like a grapefruit spoon it will be easier. Use the spoon to scoop out the insides of the onion, leaving the outer two layers intact. Be careful as you get close to the base of the onion. I left a few extra layers at the bottom so the onion would be waterproof and there would be no leakage.
- Chop the insides of the onions you hollowed out, plus the remaining onions, into a large dice.
Cook the onion filling
- Preheat a large pan to high heat and add the first butter. Add in the chopped onions. Season with salt and pepper. Cook, stirring occasionally, and changing the heat as needed, for about 45 minutes, until the onions are deep brown and have drastically reduced in size to about a cup.
- Add in the garlic, thyme, and second butter. Cook about 2 minutes. Add in the flour and stir to combine.
- Add in the broth. Stir and combine. Bring to a simmer and watch it thicken up. Simmer about 5 minutes. You want it to be very thick. Taste and adjust seasonings if needed. Remove from heat.
Stuff the onions
- Preheat the oven to 425. Add the filling to the onions and put them in a baking dish. Cook about 30 minutes.
- Meanwhile, cut the sourdough into cubes and put them on a baking sheet. Bake them for about 15 minutes.
- Top the onions first with a little cheese, then the bread, then more cheese. Smother them as much as possible and don't worry about overflow.
- Turn the broiler on and put the onions back in the oven. Broil on high for about 5 minutes until the cheese is fully melted and the bread and cheese is charring in some areas.
- Allow to cool for 5 minutes. Serve with rice.