For the entire month of January, we will be celebrating what I have named Meltuary: a celebration of all things cheesy and melty.
This week we’re making French onion soup and turning it into a fantastic, melty, and crunchy sandwich. When we’re done, we’ll have a sandwich, ready for dipping in a flavorful caramelized onion broth. Read along to find out what happens during week four of #Meltuary.
Just in case you’re unfamiliar with French onion soup, it’s a brothy soup containing onions that have been slowly cooked and caramelized into savory and sweet additions to what is typically a beef-flavored broth. A bowl of French onion soup is usually topped with slices of crusty bread that have been placed under a broiler to toast the bread and melt cheese on top.
Au jus is a French phrase that translates to “with the juice.”
One of the best parts of French onion soup is the toasty cheese-covered bread meeting the beefy and oniony broth to form a textural combination very similar to dunking a French dip sandwich into au jus. You could just stop with French onion soup, but we’re going a step further by turning this soup into a sandwich means you get that fantastic broth-dipped cheese toast experience in every single bite.
The sandwich idea
Maybe I haven’t noticed it in years past, but this year there seem to be a lot of versions of French onion-based sandwiches popping up in videos and restaurant menus. During the time between when I started planning this French onion sandwich and today, I’ve seen several content creators come out with a similar version and at least one local sandwich joint near me also has launched a French onion-focused sandwich.
Other French onion soup based sandwiches:
A more recent piece of French onion soup-based content I’ve seen recently came from my online sandwich friend, Sandwich Dad over on TikTok. Sandwich Dad makes a French Onion French Dip sandwich that will get you excited.
Also: one of my local sandwich joints, Tribecca’s Sandwich Shop, just launched its own French Onion French Dip! Here’s a little video of it over on Instagram.
Our goal of turning the soup into a sandwich elevates all the best parts of the soup and doesn’t skimp on the comforting warmth. Come along for the ride as we chart our onion soup sandwich adventure. First, we need bread.
French-style sandwich rolls
Since we’re making French onion soup, we need to make some French-style rolls. I’ve shared this recipe before, but it’s really the perfect roll for this sandwich. The chewiness of the bread and the crunchy aspects of the crust really help to stand up to the broth that will be factored into these melty sandwiches.
My recipe says that you can get 6 or 7 rolls out of this recipe and I opted for 7. That left me with around 120 grams per piece of dough. These rolls will be filled with caramelized onions and melty cheese, so for me, a smaller size works well here.
Shaping these types of rolls isn’t hard, but it requires a bit of practice and patience. The main thing I try to focus on is keeping the top of the dough as taut as possible and attempting to taper the ends when I’m rolling and shaping them.
Mine are never perfect (as you can see in the overhead photo down below), but practice helps with perfection. So, I’ll keep trying.
These French-style rolls don’t have any fat or sugar in the recipe, so you must handle this type of dough differently than typical white bread or burger buns. To get the crispy crust, you’re going to need to incorporate steam into your oven-baking process. The recipe below covers this, but basically your oven at home likely doesn’t have a steam setting, so we need to BYOS and bring our own steam to the party with water in a very hot pan inside the oven.
Here’s my French-style sandwich roll recipe that works great when you need a crusty, and chewy roll.
French onion soup
First off, we need to make French onion soup. This calls for caramelized onions which take at least 45 minutes to accomplish. After that, you add wine, beef broth, and some fresh, green herbs tied up by a string. Simmering takes half as long as the caramelization process and then you have soup.
If you don’t care about the sandwich and you just want to make French onion soup, here’s my extra comforting recipe.
Separate onions from the broth
This is the point in our process where we start to deviate from the traditional French onion soup. We want to separate the broth-simmered caramelized onions from the super savory and flavored broth. This is because we want to put onions in the sandwich and reserve the soup/broth for dipping or serving alongside the toasty onion sandwich.
Separating the onions from the broth can be done with a sieve or a strainer. I then store both the broth and the onions in separate sealed containers in the fridge. Then when it comes time to sandwich, you can easily heat both up and then build your sandwich with hot/warm onions which will help melt the cheese.
Melty sandwich press options
Since this sandwich melt isn’t using sliced bread, it requires a slightly different melt technique than the others I’ve posted about so far. Think of this sandwich more like a Cuban or a traditional panini-style sandwich on a hoagie or sandwich roll. Add a little butter to the top and bottom of the sandwich, place it on a flat, and hot surface topped by another heavy flat surface to press the sandwich, and griddle it on both sides.
I own an electric panini press, but I’m aware that not everyone does. Mine is a Cuisinart Griddler model that is right around a hundred bucks. We’ve had ours for more than 10 years at this point, so it’s been well worth the purchase for a sandwich magnate like me. It has two different plate types that can be removed and swapped so that you can have ridged grill plates and flat plates. You can also open it flat so that you have a surface for searing on if you wish (I’ve never really used this option).
But if you don’t have a panini press, you can also use two pans that fit inside each other. I’ve shared a gif here where I’m using two cast iron skillets. The big one is on the bottom where the sandwich sits and the smaller one is on top and heavy enough to weigh down the sandwich to press it.
Tip: just make sure to remember to check and clean off the bottom of the top skillet since it will be touching your sandwich.
I’ve also heard of people using a somewhat clean, heat-safe brick, wrapped in a few layers of aluminum foil as the top weight and press for a panini-style sandwich. If you dig around a tiny bit on the internet, you’ll find lots of brick chicken recipes that are using a similar tactic. Basically, you just need some way to add pressure to the top of your sandwich while heat is being applied to the bottom.
The French onion au jus melt photos and recipe
Here are photos of a few French onion au jus melts that I made recently, scroll through and check them out. The recipe is just down below as well.
Here's a super comforting sandwich and soup combo that also doubles as a crunch cheesy melt that is perfect for dipping in au jus.
Ingredients:French onion soup broth
- 5 Vidalia onions or yellow sweet onions, sliced (about 2.5 pounds)
- 2 tablespoons butter
- 1 teaspoon salt
- 1 cup white wine
- 32 ounces beef broth
- 1 fresh thyme sprig
- 1 bay leaf
- 2 parsley sprigs
- 1⁄2 teaspoon ground black pepper
- a splash of sherry wine
- 1 French-style bread rolls
- 1⁄4 cup caramelized onions (from above)
- 1⁄4 to 1⁄2 cup French onion soup broth (from above)
- 2 to 3 ounces Gruyere cheese, shredded
- 1⁄2 tablespoon butter
French onion soup: peel and cut each onion in half and then thinly slice. You should be left with a whole bunch of half-circle slices of onion. Add 2 tablespoons of butter to a medium pot over medium heat. Once the butter is melted and foamy, add all your onions. You may want to add the onion slices in batches, allowing each batch to cook and soften a bit before adding the next batch.
Once all the onions have been added, sprinkle in 1 teaspoon of salt and stir to incorporate. Allow the onions to cook untouched for about 10 minutes. After that time, stir the onions and continue cooking and stirring occasionally until they are dark brown. This process should take about 45 minutes. If you ever notice that the onions are sticking to the bottom of the pot and starting to burn, you can add a tablespoon of water and stir until the liquid boils off. This water will cool everything off and allow the onions to caramelize without burning.
Once your onions are dark brown, tie the thyme, bay leaf, and parsley together with a long piece of string or butcher's twine. This is so the herbs can float in the simmering soup, and you are able to retrieve them later.
Add 1 cup of white wine, 32 ounces of beef broth, and the tied-up herbs. Tie the other end of the string with the herbs to the handle of the pot so you can pull them out easily.
Simmer the soup for 20 minutes.
After 20 minutes, carefully taste the soup and see if it needs more salt. Add ground black pepper and salt if needed. Pour in a splash of sherry, stir the soup, simmer for another minute and then turn off the heat. Remove and discard the twine and the herbs.
Sandwich assembly: slice your roll if needed.
If your onions and broth are coming straight from the fridge, you need to warm them. You can use a microwave or two pans on the stove. The broth needs to be warm for dipping and warming the onions will help the cheese melt in the middle of the sandwich.
Add half of your cheese to the bottom of the bread roll. Top with the warm onions and then cover the onions with the rest of the cheese. Close the sandwich.
Spread butter on the top of the roll.
Cook the sandwich in a panini press until the bread gets crusty and browned. If you do not have a panini press, you can use a hot cast iron skillet with another skillet on top of the sandwich, pressing it down. This will griddle one side and you will have to flip the sandwich, but it will work just fine.
Cook the sandwich until the bread is turning golden brown and the sandwich is flattened about 5 minutes.
Serve sandwich with a small bowl of the warm au jus for dipping or for enjoying as soup alongside the sandwich.
Check back next week for the #Meltuary finale!
I’m going to serve up a new sandwich and present a few of my favorite tips and tricks I learned this month.