Description
These French Onion Sliders combine rich caramelized onions with juicy beef patties topped with melted Gruyère cheese, all nestled in soft slider buns. A perfect bite-sized twist on classic French onion flavors, these sliders are great for gatherings, game day, or a casual dinner.
Ingredients
Caramelized Onions
- 2 tablespoons unsalted butter
- 2 tablespoons olive oil
- 2 large yellow onions, thinly sliced
- ½ teaspoon kosher salt
- ½ teaspoon black pepper
- 1 teaspoon fresh thyme leaves (or ½ teaspoon dried)
- 1 teaspoon balsamic vinegar
- ½ cup beef broth
Beef Patties
- 1 pound ground beef (80/20 blend recommended)
- 1 teaspoon Worcestershire sauce
- ½ teaspoon kosher salt
- ½ teaspoon black pepper
- ½ teaspoon garlic powder
- ½ teaspoon onion powder
Assembly
- 6 slider buns
- 6 slices Gruyère cheese (or Swiss cheese)
- 2 tablespoons mayonnaise (optional)
- 2 tablespoons Dijon mustard (optional)
- 2 tablespoons chopped fresh parsley (for garnish)
Instructions
- Caramelize the Onions: In a large skillet, heat 2 tablespoons unsalted butter and 2 tablespoons olive oil over medium to medium-low heat. Add thinly sliced onions along with ½ teaspoon kosher salt and ½ teaspoon black pepper. Cook slowly, stirring occasionally, until the onions are deeply golden and soft, about 25–30 minutes. This slow caramelization builds the rich onion flavor.
- Add Seasoning and Simmer: Stir in 1 teaspoon fresh thyme leaves and 1 teaspoon balsamic vinegar. Cook for 1 more minute to incorporate flavors. Then add ½ cup beef broth and let it simmer for 5 minutes until the liquid reduces and lightly coats the onions. Remove from heat.
- Prepare the Beef Patties: In a mixing bowl, gently combine 1 pound ground beef with 1 teaspoon Worcestershire sauce, ½ teaspoon kosher salt, ½ teaspoon black pepper, ½ teaspoon garlic powder, and ½ teaspoon onion powder. Handle the meat gently to avoid tough patties.
- Form Patties: Divide the meat mixture into 6 equal portions and shape each into 2½–3 inch patties, slightly wider than the slider buns for a perfect fit.
- Cook the Patties: Heat a skillet or grill over medium-high heat. Cook the patties for 3–4 minutes on each side or until they reach desired doneness. In the last minute of cooking, place a slice of Gruyère cheese on each patty and cover the pan so the cheese melts thoroughly.
- Toast and Assemble Sliders: Optionally, lightly toast the slider buns to add flavor and structure. Spread mayonnaise and Dijon mustard on the bottom halves if using. Place the cheesy patties on the buns, then top with the caramelized onions and sprinkle fresh chopped parsley. Finish with the top buns and serve warm.
Notes
- The beef broth adds moisture and extra richness to the caramelized onions.
- Using an 80/20 beef blend keeps patties juicy while still holding shape.
- Slider buns can be toasted lightly to prevent sogginess and enhance flavor.
- Gruyère cheese melts well and adds a nutty flavor; Swiss cheese is a good substitute.
- The mayonnaise and Dijon mustard add creamy tang and moisture but are optional.
- Don’t rush the onion caramelization step; it builds the complex, sweet flavor basis for the sliders.
- Form patties slightly larger than the buns because they will shrink during cooking.
- Covering the pan when melting cheese ensures it melts evenly and thoroughly.
- Prep Time: 15 minutes
- Cook Time: 30 minutes
- Category: Sandwiches
- Method: Stovetop
- Cuisine: American