Onion Burger with Gruyère Fondue Sauce

The Fourth of July! Independence Day and the Red White and Blue! We can both recall so many family gatherings from years ago featuring foods synonymous with this American holiday. Hot dogs and hamburgers fresh off the grill with that charcoal taste, potato salad, deviled eggs, baked beans, and watermelon. Those memories are etched in our minds and are so profound that just mentioning the Holiday has an impact on our senses – especially taste and smell. Times may change, but the palate wants what the palate wants! For this holiday we decided on a low-carb Onion Burger with a Gruyère Fondue Sauce!

Caramelized Onions and Gruyère Fondue – YUM!

A burger made with onions is a classic and cheese is the usual topping. However, everyone today seems to have felt the Rachel Ray “effect.” The self-proclaimed “Queen of the Burger” has certainly made more variations than one can count. So why should we be any different? Let’s take the classic burger and cheese and add some flair – low carb, of course.

A Low Carb Bun? Absolutely!


We keep our burger simple. An 80-20 blend is our choice – the fat adds so much flavor and moisture. No one likes a dry burger. To the basic ground beef mix we add chopped onion, some garlic, and Worcestershire. In the past, we often made a burger using our basic meatloaf recipe. Lately, we just want that great grilled flavor of a simple burger and add the toppings to create a unique recipe.

The Gruyère cheese came to mind this year. Many will use a classic American cheese, or swiss, or even provolone to top a burger. Gruyère melts well and has a unique taste. You will find it in a quiche or fondue and in melted cheese sandwiches and cordon bleu recipes. It is more frequently used in French onion soup. Our fondue sauce works well with a burger. It is creamy, nutty, and with a bit of wine will add a new memory for the 4th.

Save to Pinterest – Come Back Often!

The finishing touch on our holiday burger will continue the French theme with deeply caramelized onions. We make our onions with thyme and Worcestershire and a good bit of butter. A great topping for any burger, and especially good for our Onion Burger with Gruyère Fondue Sauce. The onions need to cook low and slow.

A Soul Bread Bun is the Answer!

What would a burger be without a tasty bun? For many months we have been eating bun-less burgers or in a lettuce holder. For this holiday we went all out and used a large muffin pan and our low-carb bread recipe to make a Tasty Low Carb hamburg bun. Follow our low-carb bread recipe and fill a “mini round cake” pan 2/3 full. You will have a perfect hamburg roll.

Cooking Tips

Start with the caramelized onions first since they will take some time to turn a deep caramel color and soften. The secret is to cut your onions thin (a sweet onion is best) and brown them slowly in butter on low heat. We like a little thyme and the Worcestershire near the end of the process adds both color and flavor. Be patient – you will be rewarded with a great topping.

The key to the Guyère fondue sauce is the white wine. A dry wine works best. Try a Riesling or Chardonnay for a stronger flavor with the mellow cheese. The fondue sauce should pour easily over the burger without being too runny. If you remember the fondue years you will enjoy the taste of the beef topped with a fondue sauce.

A Delicious Low Carb Burger!

Assemble your Onion Burger with Gruyère Fondue Sauce in the usual way. A little dab of the sauce on the bottom of the bun, lettuce, then the burger. More fondue sauce on top of the burger and then capped with the caramelized onions liberally placed before topping with your low-carb bun.

Try some garlic parmesan zucchini fries on the side or our smoky bacon deviled eggs to complete the meal. Have a cold low-carb beer, enjoy the Holiday, and our simple, but tasty Onion Burger with Gruyère Fondue Sauce.

Onion Burger with Gruyère Fondue Sauce

Tastes just like a French onion soup burger - only with a creamy tasty low-carb fondue sauce.
4.93 from 14 votes
Print Recipe Pin Recipe Add to Collection
CourseSnack Meals, Main
Prep Time15 minutes
Cook Time25 minutes
Total Time40 minutes
Net Carbs6g
AuthorJoanie and Chris


Caramelized Onions

Gruyere Fondue Sauce

  • 4 ounces white wine (dry)
  • 8 ounces Gruyere cheese (shredded)
  • 1/8 teaspoon ground nutmeg
  • 1/8 teaspoon sea salt


  • 16 ounces ground beef (80-20 blend)
  • 1/4 medium onion (chopped)
  • 2 cloves garlic (chopped)
  • 1 teaspoon Worcestershire
  • 1/2 teaspoon sea salt
  • 1/8 teaspoon pepper


Caramelized Onions

  • Melt the butter in a medium skillet, pre-heated medium.
  • Add the thinly sliced onions to the melted butter and cook for 5 minutes until they wilt. Add the thyme, salt, and pepper and cook for another 10 minutes until they start to brown.
  • Add the Worcestershire sauce and cook for another 10 minutes - set aside.

Gruyere Fondue Sauce

  • Simmer the wine in a saucepan over medium heat for 5 minutes. Add the Gruyere cheese a little at a time until all melted - storing as you go to form a creamy sauce.
  • Add the nutmeg and sea salt. Keep warm until ready to assemble - consistency should be easy to pour over the burger, but not too runny. Adjust with more cheese or wine until just right.


  • Mix all of the burger ingredients in a large bowl with your hands until well incorporated. Form into patties and press your thumb in the middle of each to indent for even cooking.
  • Pre-heat grill pan to medium and spray lightly with olive oil spray. Fry until the burgers are done - about ten minutes. Flip only once and do not press down.
  • Assemble as follows - On bottom of low-carb burger bun, spread a dab of Gruyère fondue sauce. Follow with a piece of lettuce. Then the burger  and pour Gruyère cheese fondue sauce over the burger. Finally, place a good helping of caramelized onions on top and then add the burger bun lid.

Chef's Notes

If you are counting, add the nutrition information for a low-carb bun


Calories: 696kcal | Carbohydrates: 7.4g | Protein: 69.6g | Fat: 39g | Saturated Fat: 20.4g | Cholesterol: 228mg | Sodium: 412mg | Potassium: 785mg | Fiber: 1.4g | Sugar: 3.1g | Vitamin A: 1400IU | Vitamin C: 5.8mg | Calcium: 610mg | Iron: 29.2mg | Net Carbs: 6g
Like This Recipe?Follow Us @tasty_lowcarb

Free Recipes via Email

Enter your email address and receive new recipe posts via email.


  1. Hi!

    Will this recipe work if I wanted to double the fondue sauce?

    • Joan and Chris

      You can certainly double the fondue sauce recipe if you would like more on each burger. We find it is enough for two servings. There is actually a “servings” drop-down window on each recipe card where you can manually change the number off servings and it will change the recipe amounts accordingly. So, just change the servings to 4 and you will have doubled the recipe amount for the fondue automatically. We love it as a burger topping and hope you do, as well. Thanks for the comment . . . Joanie.

Comments Are Appreciated