It's not quite the ultimate French Onion Soup Burger, but it's still something we're proud of as part of our Make Your Own Epic Burger Adventure.
In a large sauté pan, heat the butter over high heat. Add the onions and cook, stirring occasionally, for about 15 minutes, until browned. Season with salt and pepper. Set aside and keep warm. Meanwhile, lay the cheese slices on the bottom half of the 4 baguette slices and toast in a toaster oven or a broiler until the cheese is melted, keep warm.
Cook the Butter-Basted Burgers. Place the burgers on each of the remaining baguette halves, top with the onions and the melted cheese and bread slice. Enjoy!