French Onion Soup Burgers

If you’ve ever dipped a spoon into a hot bowl of French onion soup and thought, “I wish I could eat this with my hands,” then this burger is for you. These French Onion Soup Burgers take everything we love about the classic soup—the caramelized onions, melty cheese, and rich savory flavor—and layer it between a toasty onion bun with a perfectly juicy beef patty. It’s indulgent, comforting, and easy enough to whip up any night of the week.

This burger started as a fun experiment one fall weekend, using leftover soup mix and some Gruyère I had tucked away in the fridge. The result? A burger that had all the richness of the bistro favorite, but wrapped in a handheld version my family couldn’t stop talking about. It’s become one of my go-to recipes when I want a burger with a little something extra.

Ingredients and Why They Matter

• Ground Beef (1.5 lbs): I like using 80/20 for a juicy, flavorful result. Each burger comes out around 6 oz—just thick enough to stay moist without being too much.
• French Onion Soup Mix (4 tbsp): Adds instant flavor without fuss. I often make my own blend to avoid extra sodium and preservatives.
• Salt + Pepper: Keep it simple; just a pinch enhances the beef.
• Onion Buns: The perfect nod to the soup’s base flavor, and they hold up well to all those juicy toppings.
• Provolone or Gruyère Cheese (4 slices): Provolone melts beautifully and has a mild flavor, while Gruyère adds a nutty sharpness—choose your favorite.
• Yellow Onions (2 large): These caramelize into sweet, golden perfection. Slice them thinly so they cook evenly.
• Butter (2 tbsp): Helps coax out the natural sugars in the onions for that deep, rich color.
• Water (¼ cup + more as needed): Helps prevent burning while the onions cook down slowly.
• Brandy or Sherry (1–2 tsp, optional): Adds that hint of depth you recognize from restaurant-style French onion soup. Totally optional, but worth it.
• Dried Thyme (pinch, optional): A little earthy flavor that rounds things out.

Step-by-Step Instructions for French Onion Soup Burgers

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Step 1: Make the Burger Patties

In a mixing bowl, gently combine the ground beef with the French onion soup mix. Be careful not to overmix—it keeps the patties tender. Divide into four equal parts and shape into patties slightly larger than your buns. Season both sides lightly with salt and pepper. Set aside while you prepare the onions.

Step 2: Caramelize the Onions

Melt butter in a skillet over medium heat. Add the sliced onions and ¼ cup water. Cover and cook for 10 minutes to start breaking them down. Then uncover and stir frequently, letting the onions soften and slowly brown. Add water a tablespoon at a time as needed to prevent sticking. Once they’re a deep golden color and silky in texture, stir in the brandy or sherry and thyme (if using), then remove from heat.

Step 3: Cook the Burgers

Grill or pan-fry the patties over medium-high heat, about 4–5 minutes per side or until your desired doneness. In the last minute of cooking, place a slice of cheese on each patty and cover the skillet (or close the grill lid) to melt.

Step 4: Assemble the Burgers

Lightly toast the onion buns if desired. Place a cheesy patty on each bottom bun, then top with a generous pile of caramelized onions. Add the top bun, press gently, and serve hot.

The trick to making these burgers unforgettable is the onions. Don’t cut corners here—let them cook until they’re golden, soft, and almost jammy. It takes time, but it’s worth every second.

Variations and Substitutions to Try

• Use ground turkey or chicken: A lighter take that still pairs beautifully with caramelized onions and melty cheese.
• Make it spicy: Add crushed red pepper to the onions or smear Dijon mustard on the bun.
• Add sautéed mushrooms: For an even deeper umami flavor.
• Serve open-faced: Pile the burger and onions on a slice of toasted sourdough and serve with a knife and fork.

I’ve even made sliders with this recipe for game day—just use mini buns and smaller patties. They disappear fast.

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Chef’s Helpful Tips

• Make your own French onion soup mix for more control over sodium
• Use a cast-iron skillet for even searing and better browning
• Store caramelized onions in the fridge—they keep for 3–4 days and reheat well
• Use a meat thermometer if unsure—medium doneness is around 160°F for beef

These French Onion Soup Burgers bring serious flavor to the table, whether you're cooking for the family or just treating yourself to something a little extra on burger night. They’re warm, cheesy, a little sweet, a little savory—and totally unforgettable.

Frequently Asked Questions

• Can I make the onions ahead of time?
  Yes! Caramelized onions keep well in the fridge for up to 4 days and reheat perfectly.
• What’s the best cheese for this recipe?
  Gruyère for traditional French onion flavor, or provolone for a smoother, cheesier melt.
• Can I grill the burgers instead of pan-frying?
  Absolutely. Just be sure to melt the cheese at the end by covering the burgers briefly.
• Is there a substitute for the French onion soup mix?
  You can make a homemade version using onion powder, beef bouillon, garlic powder, and a pinch of sugar.
• Can I freeze the patties?
  Yes, form and freeze them raw with parchment between layers. Thaw before cooking.