French Onion Stuffed Burgers Au Gratin Recipe

Ingredients For French Onion Stuffed Burgers Au Gratin Recipe

• 1 tablespoon Olive oil
• 2 Large onions halved and thinly sliced
• 0.5 teaspoon Kosher salt
• 0.25 teaspoon Pepper
• 0.25 cup Beef broth
• 0.25 cup Red wine or additional beef broth
• 0.25 cup Mayonnaise
• 0.25 cup Plain greek yogurt
• 2 tablespoon The onion mixture
• 1 teaspoon Dijon mustard
• pinch Pinch Salt And Pepper To Taste
• 1.33 pound Lean Ground Beef
• 0.5 teaspoon Pepper
• 1 teaspoon Kosher salt
• 4 ounce Gruyere cheese shredded, divided
• 4 Brioche buns or gluten free buns, if needed, sliced open
• Bibb or butter lettuce