French Onion Soup Burgers

This burger transforms the classic flavors of French onion soup into a mouthwatering handheld feast. The sweet caramelized onions combined with melty Gruyère cheese create a sophisticated twist on a traditional burger that's sure to impress even the most discerning dinner guests.

I first created these burgers when looking to elevate our family's weekend cookout. The moment my husband bit into one, his eyes widened and he declared it might be the best burger he'd ever tasted. Now it's our signature dish when entertaining friends.

Ingredients

• Ground beef: Choose 80/20 lean to fat ratio for the juiciest burgers with optimal flavor
• Large onions: Yellow onions work best as they caramelize beautifully and develop the perfect sweetness
• Butter: Use unsalted to control the overall saltiness of your burger
• Sugar: Helps accelerate the caramelization process for those golden brown onions
• Beef broth: Adds depth and prevents burning while caramelizing onions
• Worcestershire sauce: Provides umami richness and enhances the beef flavor
• Fresh thyme: Brings an aromatic herbaceous note that complements both the beef and onions
• Gruyère or Swiss cheese: These alpine cheeses have the perfect melt and nutty flavor that echoes traditional French onion soup
• Hamburger buns: Brioche buns offer a slight sweetness and rich texture that elevates the burger
• Garlic: Adds aromatic depth to the butter for toasting the buns

Step-by-Step Instructions

Caramelize the Onions:

Place butter in a large skillet over medium heat until melted and slightly bubbling. Add thinly sliced onions and sprinkle with sugar. Cook slowly for 20-25 minutes, stirring occasionally with a wooden spoon. Watch for the onions to gradually transform from white to golden to deep amber. If they begin to stick to the pan, add a splash of beef broth and scrape up the flavorful browned bits. The onions are ready when they're deeply golden and sweet smelling.

Prepare the Beef Patties:

In a large mixing bowl, add ground beef, salt, pepper, and Worcestershire sauce. Use your hands to gently combine the ingredients without overworking the meat. Divide the mixture into four equal portions and shape into patties slightly larger than your buns, as they'll shrink during cooking. Press your thumb into the center of each patty to create a small dimple, which prevents the burgers from puffing up in the middle.

Cook the Burgers:

Heat a cast iron skillet or grill to medium high heat. Place the patties on the cooking surface and cook for approximately 4 minutes on the first side for medium doneness. Flip once and cook for an additional 3-4 minutes or until your desired doneness is reached. Avoid pressing down on the patties with a spatula as this releases the flavorful juices.

Prepare Garlic Butter Buns:

In a small bowl, mix minced garlic with softened butter until well combined. Split hamburger buns and spread the garlic butter mixture on the cut sides. Place under the broiler or on the edges of your grill for 1-2 minutes until golden brown and crispy around the edges.

Assemble the Burgers:

Place each cooked patty on the bottom half of a toasted bun. Top generously with caramelized onions, making sure to distribute them evenly. Place a slice of Gruyère or Swiss cheese on top of the onions. Place under the broiler for about 1 minute or until cheese is melted and bubbling.

Finish and Serve:

Sprinkle fresh thyme leaves over the melted cheese for a fragrant finish. Place the top bun over the cheese and press gently. Serve immediately while hot with your choice of sides.

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I've experimented with countless burger recipes over the years, but the caramelized onions are truly the star here. My grandmother always said patience is the secret ingredient in great cooking, and nowhere is this more true than when coaxing the natural sugars from onions. The aroma that fills my kitchen during this process instantly transports everyone who walks in to a cozy Parisian bistro.

Make Ahead Options

These burgers offer excellent make ahead potential for stress free entertaining. The onions can be caramelized up to three days in advance and stored in an airtight container in the refrigerator. Simply reheat them gently in a skillet before assembling your burgers. The garlic butter can also be prepared in advance and stored in the refrigerator. Allow it to soften at room temperature before spreading on buns. Even the patties can be shaped a day ahead and kept covered in the refrigerator until ready to cook.

Elevate Your French Onion Soup Burger

For a truly spectacular presentation, consider serving these burgers open faced with extra cheese and a quick trip under the broiler. The melted, bubbly cheese cascading over the sides evokes the traditional gratinéed appearance of classic French onion soup. Another delicious variation is to deglaze the onion pan with a splash of cognac or dry sherry before adding the beef broth, which adds another layer of authentic French onion soup flavor.

Perfect Pairings

These sophisticated burgers deserve thoughtful accompaniments. A simple arugula salad dressed with lemon vinaigrette provides a peppery, acidic counterpoint to the rich burger. For a heartier meal, serve alongside homemade potato wedges tossed with herbs de Provence. To drink, consider a medium bodied red wine like Pinot Noir or a crafty amber ale that can stand up to the robust flavors without overwhelming them.

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Frequently Asked Questions

→ How long should I caramelize the onions?

Caramelize the onions for about 20-25 minutes over medium heat until they reach a deep golden brown color. Be patient with this process as proper caramelization develops the sweet, rich flavor that makes these burgers special. If the onions start to stick, deglaze the pan with a splash of beef broth.

→ Can I substitute the cheese?

Yes! While Gruyère cheese provides the most authentic French onion soup flavor with its nutty characteristics, Swiss cheese works well as mentioned in the ingredients. Other good alternatives include Comté, Emmental, or even provolone if you prefer a milder flavor.

→ How do I prevent my burgers from puffing up in the middle?

Create a slight dimple or depression in the center of each raw patty with your thumb before cooking. As the burger cooks and the proteins contract, this depression will fill out, resulting in a flat, evenly-cooked burger rather than one that's puffed in the middle.

→ What sides pair well with these burgers?

These burgers pair beautifully with crispy French fries, a simple green salad with vinaigrette, or even a small cup of beef broth for dipping (to further emphasize the French onion soup connection). For an elegant touch, serve with truffle fries or a light arugula salad.

→ Can I make the caramelized onions ahead of time?

Absolutely! Caramelized onions can be made 2-3 days in advance and stored in an airtight container in the refrigerator. This is actually a great time-saving strategy, as the onions take the longest to prepare. Simply reheat them gently before assembling your burgers.

→ How can I make these burgers more authentic to French onion soup?

For an even more authentic French onion soup experience, you can add a splash of dry sherry or red wine when deglazing the onions, use a crusty bread like a sliced baguette instead of burger buns, or even serve some extra beef broth on the side for dipping.