The French Onion Patty Melts Plated with fries on a cutting board.

If you love a good patty melt and french onion soup, then why not combine the two? This French Onion Patty Melt is the perfect handheld.

We’re talking melty gruyere cheese, caramelized onions, double patties, and double swiss cheese, all toasted up on a skillet and served with a classic diner sauce—yum!

Serve this with some fries, and you’ve got a delicious meal!

What is a French Onion Patty Melt?

A French Onion Cheesy Patty Melt after it's been sliced.

A classic patty melt consists of ground beef patties, melted cheese, and caramelized onions on two pieces of bread toasted by the flames.

This version of a patty melt combines the toasty, cheesy goodness of a patty melt and the deliciously classic flavor of french onion soup. It makes for a pretty freaking good patty melt sandwich!

If you like french onion soup, then you should try my Tomahawk Steak with French Onion Crust.

How to Make a It!

French Onion Patty Melt Ingredients


  • Ground Beef  (I used 80/20 ground beef for this recipe because it makes for a juicy burger and holds together well when being cooked)
  • Swiss Cheese (for nuttiness)
  • Gruyere Cheese (for it’s deep smokey flavor)
  • Kosher Salt
  • Black Pepper
  • Garlic Powder (put this in everything)


  • Yellow Onions (yellow onions have the best flavor for caramelizing)
  • Brown Sugar (adding a bit more sweetness)
  • Kosher Salt
  • Black Pepper
  • Garlic Powder (Yes, more garlic.)

Diner Sauce:

  • Ketchup
  • Yellow Mustard
  • Mayonnaise
  • Pickle Relish  (gives it a zip and provides some texture to the sauce)
  • Hot Sauce (you can select a mild sauce if you are sensitive to spice)


  • Thick Cut Bread (white bread or slices of rye bread will do)
  • French Fries (or potato chips if you prefer)
  • Pickles

French Onion Patty Melt Instructions

The first thing we need to do is form our hamburger patties, so section your beef into 1/3 pound balls.

No one likes a crumbly burger patty, so place the formed patty balls on a tray and set them in the fridge for about 25-30 minutes. This will give them time to set up so they don’t fall apart when you cook them.

The burger patties cooking on the skillet.

Next, toss together all the ingredients for your diner sauce and then place that in the fridge. We are using ketchup, yellow mustard, mayo, pickled relish, and hot sauce.

We love this diner sauce because it’s super easy to make. Heck, you probably already have everything you need on hand!

Now it’s time to cook your patties. Preheat your grill to medium-high heat (340F), add a large cast iron skillet, and pull your tray out of the fridge.

Smashing the burger balls into patties.

For this next step, you’ll want to grab a piece of parchment paper and a spatula. Place each burger onto the skillet and then put a piece of parchment paper over it. I like to put the parchment paper between my spatula and the patty because it helps prevent the beef from sticking to my spatula.

Use the spatula to smash the hamburger patty onto the skillet, and repeat for each patty.

If you like smashed patties, then you’ll love my Steakhouse Smash Burgers, Elvis Smash Burger and Cheesy Onion Smash Burgers.

Make sure to carefully flip each burger over and season the exposed side with salt, pepper, and garlic. Once they are done cooking, pull them off the heat and keep them warm until you’re ready to assemble your French Onion Patty Melt.

Adding the onions to the skillet for the French Onion Patty Melts.

French Onions for Our Patty Melts

Now for the best part, add your sliced onions to the skillet and allow them to caramelize. I recommending grabbing something to sip on because it should take the onions around 30-45 minutes to turn dark brown. About halfway through the cooking time, add salt, pepper, garlic, and brown sugar.

The onions as they brown on the skillet over the flames.

There’s nothing like the smell of grilled onions to make your mouth water! Once your onions are fully caramelized, pull them off the heat and keep them warm.

French Onion Patty Melt Assembly

Now you’re ready for assembly! Add a spoonful of that delicious diner sauce to the bottom piece of bread, a sprinkle of gruyere cheese, and some caramelized onions.

The assembly of the French Onion Patty Melt.

On top of that, add your first patty with a slice of swiss cheese. Next comes your second patty, more swiss cheese, caramelized onions, gruyere cheese, and another slice of bread with diner sauce.

Repeat this process until all your patty melts are assembled. 

Place each patty melt on a clean hot cast iron skillet so that the bread will toast. It should take about 1-2 minutes for your bread to turn golden brown.

The French Onion Patty Melt's assembled and getting toasted over the fire.

Make sure you don’t walk away because no one wants a burnt patty melt! Once you’ve achieved your desired toastiness,  it’s time to dig in!

Serve with fries, ketchup, and pickles—enjoy!

The French Onion Patty Melts ready to devour.

For more delicious sandwich style recipes, check out my BBQ Steak Sandwich, Cheese Stuffed Sausage Sandwich and Crispy Korean Pork Belly Sandwiches.

How to Store French Onion Patty Melt

These sandwiches are best enjoyed fresh, but if you have leftovers, the best way to store them is deconstructed in an airtight container. You don’t want to keep them with the bread and diner sauce because you’ll be left with a soggy sandwich, and who wants that?

Maybe my dogs, but that’s it.

If you do end up with a leftover assembled patty melt, you can always reheat it by placing it in the oven for 5 minutes at around 375F until the outside is once again crispy!


What is the difference between a patty melt and cheeseburger?

A patty melt is a variant of your classic American cheeseburger. The main difference between the two is that a cheeseburger is served on a soft bun while a patty melt comes on griddled bread.

Can you reheat a patty melt in an air fryer?

An air fryer is a good option for reheating your patty melt! Place it in the basket at about 350 to 400 degrees and let it heat up for around 4 minutes until your desired level of crispiness is achieved.

There’s nothing like this classic diner sandwich. If a regular burger sounds boring to you, give this French Onion Patty Melt recipe a try, it’s so freaking delicious!

The combination of savory caramelized onion, melty cheese, and burger patties topped with diner sauce is like your favorite grilled cheese sandwich only ten times tastier. 

This French Onion Patty Melt gives you that savory, salty, but slightly sweet kick you just can’t get enough of. Let us know how yours turned out in the comments!

For more delicious recipes, check out my second cookbook Flavor X Fire or my first cookbook Food X Fire!

Needing more spice in your life? My spice line can help with that. Check them out here.

Want to save this recipe?
Enter your email and get it sent to your inbox! Plus, you’ll get freakin’ delicious recipes every week.
Please enable JavaScript in your browser to complete this form.
The French Onion Patty Melts ready to devour.

French Onion Patty Melt

French Onion Patty Melt is your favorite patty melt, but with some sweet and tangy onions on top!
Author:Derek Wolf
No ratings yet
Prep Time: 30 minutes
Cook Time: 1 hour
Total Time: 1 hour 30 minutes
Course: Main Course
Cuisine: American
Servings: 4 People



  • 2 lbs Ground Beef 80/20
  • 12-14 sliced Swiss Cheese
  • 1.5 cups Gruyere Cheese
  • 1.5 tbsp Kosher Salt
  • 1.5 tbsp Black Pepper
  • 1.5 tbsp Garlic Powder


  • 2 Yellow Onions thinly sliced
  • 2 tbsp Brown Sugar
  • 1 tsp Kosher Salt
  • 1 tsp Black Pepper
  • ½ tsp Garlic Powder

Diner Sauce:

  • 2 tbsp Ketchup
  • 2 tbsp Yellow Mustard
  • 2 tbsp Mayonnaise
  • 1 tbsp Pickled Relish
  • 1.5 tsp Hot Sauce


  • 6-8 slices Thick Cut Bread
  • French Fries for serving
  • Pickles for serving


  • Begin by loosely forming 2.5-3 oz balls of ground beef, set onto a tray and place in the fridge to firm for 30 minutes. In another bowl, mix together all the ingredients for your Diner Sauce and set that in the fridge until you are ready.
  • Preheat your grill to medium high heat (around 350F) adding a cast iron skillet/plancha to the grill 2 minutes before cooking.
  • Pull your burger patties out of the fridge and add to the skillet. As the meat sizzles, get out a small piece of parchment paper and a larger spatula/burger smasher. Place the parchment over one ball and then firmly press with the spatula until the burger is “smashed” on the skillet. Repeat this for each burger and let cook for another 1-2 minutes. Carefully flip each burger over and then season the new side with salt, pepper and garlic. Pull off and keep warm until ready to use.
  • Next, add your sliced onions to the skillet and begin caramelizing. Slowly cook the onions until they turn dark brown (about 30-45 minutes). About halfway through the cook, add the salt, pepper, garlic and brown sugar. Stir and keep cooking. Once done, pull off and keep warm.
  • Start assembling your patty melt with a spoonful of the Diner Sauce on the bottom piece of bread, handful of caramelized onions, sprinkle of gruyere cheese, 1 patty, slice of swiss cheese, another patty, more swiss cheese, caramelized onions, gruyere cheese and another slice of bread with diner sauce. Repeat this for all the patty melts, then place them on a clean skillet/plancha to toast the bread. Cook for 1-2 minutes per side until golden brown, then pull off and let cool.
  • Serve your patty melts with fries, ketchup and pickles. Enjoy!



Calories: 1253kcal | Carbohydrates: 47g | Protein: 75g | Fat: 85g | Saturated Fat: 37g | Polyunsaturated Fat: 7g | Monounsaturated Fat: 30g | Trans Fat: 3g | Cholesterol: 266mg | Sodium: 4289mg | Potassium: 1069mg | Fiber: 5g | Sugar: 19g | Vitamin A: 967IU | Vitamin C: 10mg | Calcium: 1109mg | Iron: 7mg

Derek Wolf

Derek is the driving force behind Over the Fire Cooking. He started cooking with live fire in 2016 and decided to start a social media page so his friends and family could follow the journey. Fast forward to today and Over the Fire Cooking has spread across multiple platforms with millions now following Derek's fire cooking journey. He's a southern fellow who enjoys everything from classic BBQ to Central and South American inspired dishes. Whatever he's cooking up, it's guaranteed to be so freakin' delicious!

Leave a comment

Your email address will not be published. Required fields are marked *

Recipe Rating


  1. Derek – sounds fantastic. Question – why not do the onions first? Is it because you want to use the beef fat/drippings for the onions?

    1. Yes I wanted to cook the onions in the fat and the searing of the bread would help with reheating the burgers.