French Onion Burgers (Like Soup But in Burger Form!)

Published: Jul 6, 2024 Modified: Jul 7, 2024 Author: Christina

Try this French onion burger for a fun twist on the classic soup we all know and love! Incredibly juicy and flavorful burger patties spiced with fresh garlic, thyme, and Worcestershire sauce, topped with mouthwatering caramelized onions and a mix of melted Gruyère and provolone cheese.

There’s just something special and iconic about hot-off-the-grill burgers in the summer, and I mean good burgers– juicy, flavorful hamburgers topped with melted cheese. While I focus on burgers in May with my annual Burger Week, I certainly don’t limit burger-making to that timeframe.

Today we are adding a new one to the list of burger favorites: French onion burgers. A classic soup turned burger! It has layers of flavor from the patties, to caramelized onions and the gooey melted cheese… all sitting on a toasted hamburger bun. THE ABSOLUTE BEST. You’ll most certainly love this French onion burger recipe just as much as taste testers did too!

Why You’ll Love This French Onion Burger

• A twist on the classic French onion soup, in burger form!
• Flavor explosion in every bite
• Mouthwatering caramelized onions
• Extra juicy– no dry burger!
• Will be a hit with family and friends

You Need These Ingredients

• Beef: The most important ingredient, ground beef. I usually use 85-90% lean ground beef. The higher percentage, the leaner the meat. Remember, fat adds flavor so I recommend 87% for the best results.
• Onion: You need 2 sweet onions, thinly sliced. It’s important to slice them of even thickness so they caramelize evenly.
• Butter: The butter is key for caramelizing the onions.
• Beef Broth: For the iconic flavor, we’re using beef broth to reduce down the onions.
• Flour: We’re using all-purpose flour to help thicken the onion mixture– you don’t need much, just 2 Tablespoons. There is no other substitutions that I’ve tried.
• Cheese: To mimic the classic soup, use Gruyère and provolone cheese for the best flavor.
• Worscestershire Sauce: Just like many other burger recipes or these chicken meatballs, the Worcestershire sauce adds a deep unbeatable flavor. There’s no substitutions for it.
• Salt & Pepper: Essential for flavor.
• Thyme & Garlic: Fresh is best, both add a tremendous amount of flavor.

How To Make French Onion Burgers

The full detailed printable recipe is below in the recipe card, but let’s walk through the steps.

1. Caramelize the Onions: Sauté the butter, onions and salt over medium heat for 30 minutes, stirring every few minutes, until the onions are very soft and golden brown. Stir in the garlic and thyme. Then, add the flour and beef broth and cook until thickened.
2. Form the Burgers: Combine the ingredients in a large bowl and combine. The best way to do this is with your hands, though you can also use a wooden spoon for rubber spatula as well. Divide the ground beef mixture into 6 sections, roughly a heaping ½ cup for each. Form each patty freeform or use a burger mold– each patty will be around 4-5 inches wide.
3. Grill the Burgers: Place the burgers on the heated grill and cook for 5 minutes with the lid closed. Flip the burgers and cook covered for an additional 4-5 minutes or until a meat thermometer reads 150°F. About 1 minute before the burgers finish, top with cheese slices.
4. Assemble the Burgers: Place the burger on a toasted hamburger bun and top with caramelized onions. Add additional toppings if desired.

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French Onion Burgers

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Try this French onion burger for a fun twist on the classic soup we all know and love! Incredibly juicy and flavorful burger patties spiced with fresh garlic, thyme, and Worcestershire sauce, topped with mouthwatering caramelized onions and a mix of melted Gruyère and provolone cheese.

• Author: Christina
• Prep Time: 15 minutes
• Cook Time: 45 minutes
• Total Time: 1 hour
• Yield: 6 burgers
• Category: Dinner
• Method: Grill

• 4 Tablespoons unsalted butter
• 2 sweet onions, thinly sliced
• 1 ½ teaspoons salt, divided
• 2 teaspoons minced garlic, divided
• 1 teaspoon fresh thyme, minced
• 2 Tablespoons all-purpose flour
• ½ cup low-sodium beef broth
• 2 pounds 85-87% lean ground beef
• 2 teaspoons Worcestershire sauce, divided
• 1 teaspoon black pepper, divided
• 8–10 slices Gruyère or provolone cheese (or both!)
• for serving: hamburger buns, additional toppings like lettuce, tomatoes, pickles, etc.

Instructions

1. In a large skillet over medium heat, add the butter and onions. Sauté for 5-7 minutes until the onions begin to soften. Add ½ teaspoon salt and cook for 30 minutes, stirring every few minutes, until the onions are very soft and golden brown. If the onions start to stick to the pan, reduce the heat to medium-low. Stir in ½ teaspoon thyme and 1 teaspoon garlic, and let it cook for 1 minute. Stir in the flour and cook for 2-3 minutes to remove the flour taste. Then, whisk in the beef broth until the onion mixture thickens. Remove from the heat and set aside.
2. Line a large baking sheet or plate with parchment paper. Set aside. Combine the ground beef, Worcestershire sauce, black pepper, and remaining salt, garlic, and thyme. Mix together until combined– the best way to do this is with your hands or with a wooden spoon or rubber spatula.
3. Divide the ground beef mixture into 6 sections, roughly a heaping ½ cup for each (for 8 burgers, use a heaping ¼ cup for each.) Form each patty freeform or use a burger mold– each should be around 4-5 inches wide (about 1 inch larger than the bun as the burgers will shrink as they cook.) Place each formed patty onto the prepared baking sheet while you form the remaining. The total cook time is 9-10 minutes. Let the patties rest for 5 minutes while the grill preheats in the next step. This can be done while the onions are cooking.
4. Preheat the grill to high (500ºF-550ºF.) Place the burgers on the heated grill and cook for 5 minutes with the lid closed. Flip the burgers and cook for an additional 4-5 minutes or until a meat thermometer reads 150ºF. About 1 minute before the burgers finish, top with cheese slices and close the lid to allow the cheese to melt. Keep an eye on the burgers as the time can vary slightly based on the thickness of the patty (thinner patties = less time.) Set the cooked burgers on a baking sheet or plate covered with aluminum foil and allow them to rest for 2-3 minutes to allow the juices to redistribute throughout the burger. The patties will not stick to a clean, well-oiled surface or grill. 
5. Serve on a toasted hamburger bun, topped with caramelized onions and additional desired toppings such as lettuce, tomato, mayo, pickles, or whatever your favorite toppings are. Leftover burgers stay fresh in the refrigerator for up to 5 days.

Notes

1. Make Ahead Instructions: You can shape the burger patties up to 2 days in advance. Place parchment paper between each and store in an airtight container or bag on a flat surface. The caramelized onions can be made up to 3 days in advance. Reheat over low heat or in the microwave.
2. Freezing Instructions: Uncooked patties can be frozen for up to 3 months. Place parchment paper between each and store in a freezer-safe airtight container. Thaw overnight in the refrigerator and cook as directed in step 4, or you can grill from frozen for an additional 3-5 minutes. The cooked burgers can be frozen for up to 3 months, allow them to cool completely then place parchment paper between each and store in a freezer-safe container or bag. Thaw overnight in the refrigerator and heat up to your liking.
3. Ground Beef: The leaner the ground beef the more dry the burger will be. I recommend 87% lean for the best results.
4. Onions: Make sure the onions are evenly sliced to allow for even cooking. I recommend thinly slicing as it speeds up the caramelization process and time.
5. Make 8 Burgers: Instead of 6 burgers, you can make 8 using a heaping ¼ cup of the ground beef mixture. The cook time will be slightly less since it’s a thinner patty.
6. Cook Times: You can use the following temperatures depending on preference (1) medium-rare 130ºF-135°F, (2) medium 140ºF-145°F, (3) medium-well 150ºF-155°F (4) well done 160°F+.