The French Onion Soup Burger: A Grilled Masterpiece

How to Make the Ultimate French Onion Soup Burger

French onion soup ranks among the world’s most comforting dishes—rich, savory broth, sweet caramelized onions, and gooey cheese. This burger reinvents those flavors on the grill, pairing a juicy, cheese-stuffed patty with grilled onions and using toasted French bread in place of a traditional bun. The result is a sandwich that delivers the best of soup and burger worlds in each indulgent bite.

Prepping the Onions for Maximum Caramelization

Begin by selecting sweet Vidalia or other mild yellow onions. To keep thick slices intact while grilling, thread each onion with three or four bamboo skewers before slicing into rounds. This “onion pop” technique yields lollipop-style cuts that hold together on the grate and slide perfectly onto the burger later. Pat the slices dry to remove excess moisture, which helps them brown evenly.

Crafting the Seasoned Beef Patties

For the patties, use 80/20 ground beef for an ideal balance of juiciness and flavor. In a bowl, combine the meat with a teaspoon of beef bouillon base, a teaspoon of dried chives, freshly ground black pepper, and a tablespoon of minced garlic. Mix gently to avoid overworking the meat, then divide into eight thin patties. Arrange four of the patties on a tray, top each with a slice of Gruyère, and seal with the remaining patties, pinching the edges tightly to trap the cheese inside.

Choosing French Bread as the Bun Alternative

Instead of a standard hamburger bun, slice a sturdy loaf of French bread into thick, crouton-like rounds. These toasty rounds crisp beautifully on the grill and soak up melting cheese and beef juices, mimicking the texture of a crouton in classic French onion soup.

Grilling on a Wood Pellet Grill

Heat your pellet grill to 450 °F using oak pellets for a subtle smoky note. Place the stuffed patties on the grate, close the lid, and let them cook ten minutes before flipping. After the turn, grill for an additional ten to fifteen minutes, or until the internal temperature reaches 160 °F. Meanwhile, brush the onion rounds and bread slices lightly with melted butter and a pinch of salt. Toast them on the grill until golden and slightly crisp, watching carefully to prevent burning.

Building the French Onion Soup Burger

To assemble, start with a toasted bread round, then add the cheese-filled burger patty. Top with a thick grilled onion slice and an extra slice of Gruyère or provolone for added melt. Crown with a second bread round for a rich, buttery “crouton” bun that holds all the juicy, savory flavors together.

This French Onion Soup Burger, also known in Bill’s cookbook as “Bill’s Best French Onion Burgers,” merges the deep sweetness of caramelized onions, the stretch of melted Gruyère, and the satisfying crunch of grilled bread. It’s a creative twist that proves soup and sandwich can share the spotlight on your backyard grill.

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Bill is the creator of Barbecue Tricks and author of the Big Book of BBQ Tricks. Drawing inspiration from the birthplace of American barbecue, he shares straightforward, flavor-packed grilling techniques that elevate backyard cooking to restaurant quality.

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Enjoy Bill’s Cook Book as well: Big Book of BBQ Tricks: 101+ Tricks, Secret Ingredients and Easy Recipes for Foolproof Barbecue & Grilling