Smashburger French Onion Burger: Gourmet Taste at Home

The first time I sank my teeth into Smashburger’s French Onion Burger, I knew I had to recreate this masterpiece at home. This gourmet burger combines the rich flavors of caramelized onions with the creamy decadence of Boursin and Swiss cheese, all nestled on a toasted onion bun. Originating from Smashburger’s limited menu, this French-inspired creation elevates the humble hamburger to extraordinary heights with its unique cheese combination and signature smashing technique that locks in flavor and juiciness.

This post contains affiliate links. As an Amazon Associate, I earn from qualifying purchases.

What makes the Smashburger French Onion Burger so special

The magic of this burger lies in the smashing technique, which creates a flavorful crust while sealing in juices. Using minced chuck steak instead of regular ground beef provides superior flavor and texture. The combination of creamy Boursin and melty Swiss cheese creates a luxurious sauce-like element that eliminates the need for traditional condiments. Caramelized onions add a sweet depth that complements the savory meat perfectly.

Ingredients

• Chuck steak, minced – Provides superior flavor and juiciness compared to regular ground beef
• Boursin cheese – Offers a creamy, herbaceous element that elevates the burger beyond ordinary offerings
• Swiss cheese – Adds a nutty flavor and perfect meltability for a gooey texture
• Yellow onion – Creates sweet caramelized flavor that defines the French onion profile
• Butter – Helps onions caramelize properly and adds richness
• Onion buns – Enhances the overall onion flavor theme throughout the burger, brioche burger buns are an excellent substitute
• Olive oil – Creates the perfect sear on the patties
• Salt – Enhances the natural beef flavor
• Black pepper – Adds subtle heat and complexity
• Garlic powder – Provides aromatic depth to complement the onion flavor

Step-by-Step Instructions

1. Prepare burger seasoning in a small bowl by combining kosher salt, ground black pepper, and garlic salt.
2. If using whole chuck steak, cut into 1-inch cubes and pulse in a food processor until coarsely ground, or ask your butcher to mince it fresh.
3. Divide the minced chuck into 8 equal portions and gently form into loose balls.
4. Heat your grill to about 350 degrees, or medium-high heat.
5. Melt butter on the grill and add thinly sliced yellow onions.
6. Sprinkle the burger seasoning on the onions and sauté until tender, being careful not to brown them.
7. Butter both sides of the onion buns and place them on the grill.
8. Cook the buns until they are lightly browned, then remove from the grill.
9. Place the meat balls on the hot grill, leaving plenty of space between them.
10. Using a metal spatula, firmly smash each meat ball flat onto the grill surface.
11. Season the burger patties with the burger seasoning mixture.
12. Cook for 2-3 minutes until the bottom is well-seared.
13. Flip the patties and continue cooking on the other side.
14. Place 1 slice of Swiss cheese on each burger while they’re still on the grill and allow to melt.
15. Build the burger by placing two cheese-topped patties on the bottom burger bun.
16. Top the patties with the grilled onions.
17. Spread Boursin cheese on the top bun and place it on top of the assembled burger.

Love A great burger? Try these Smashburger Recipes and more!

Smashburger Buffalo and Blue Cheese
Smashburger Truffle Mushroom Swiss
Smashburger Smashsauce
Copycat Applebees Quesadilla Burger

Copycat Smashburger French Onion Burger

An indulgent burger featuring caramelized onions, creamy Boursin, and melty Swiss cheese on a toasted onion bun,

5 from 11 votes

Print Pin Rate Add to Collection Go to Collections

Course: Main Course

Cuisine: American

Keyword: Burger, French Onion Burger, Smashburger French Onion Burger

Prep Time: 10 minutes minutes

Cook Time: 15 minutes minutes

Total Time: 25 minutes minutes

Servings: 4

Calories: 859kcal

Author: Stephanie Manley

Ingredients

• 4 Onion Buns
• 1 white onion sliced thin
• 1 tablespoon butter
• 2 pounds ground beef
• 8 slices swiss cheese
• Boursin cheese
• 2 teaspoons kosher salt
• 2 teaspoons ground black pepper
• 2 teaspoons garlic salt

Instructions

• Prepare burger seasoning, and use for the recipe. In a small bowl combine the kosher salt, ground black pepper, and garlic salt. 
• Saute onions with butter on the grill. Sprinkle burger seasoning on the onions. Cook the onions until they are tender. Do not brown the onions. 
• Butter each of the buns and cook the buns on the grill. Cook the buns on the grill until they are lightly brown.
•  Form 8 balls of the burger meat. Heat the grill to about 350 degrees. Place the balls on the grill. Smash burger meat onto the grill. Season with burger seasoning. 
• Cook for 2 to 3 minutes flip and continue to cook on the other side. Place 1 slice of Swiss cheese on each burger while they are on the grill. 
• Build the burger by building up from the bottom by adding the two burgers with cheese on each bun. Then top with grilled onions, and spread some Boursin cheese on the top bun. Top the burger with the top bun.

Notes

For the most authentic Smashburger experience, use a metal spatula with a sharp edge and press down firmly when smashing—don’t be gentle! The key is to smash quickly after placing the meat on the hot grill. This creates the signature crispy edges that make Smashburger unique. For even better results, chill your meat balls for 15 minutes before cooking to help them hold together during the smashing process. Keep your onions tender but not browned for the proper flavor profile, and don’t skip buttering and toasting the buns—it makes a significant difference in texture and taste.

Nutrition

Calories: 859kcal | Carbohydrates: 4g | Protein: 54g | Fat: 67g | Saturated Fat: 31g | Cholesterol: 230mg | Sodium: 2675mg | Potassium: 668mg | Fiber: 0g | Sugar: 1g | Vitamin A: 655IU | Calcium: 495mg | Iron: 4.8mg