Creating French Onion Smashburgers is a straightforward process. Follow these simple steps to achieve burger perfection:

1. Caramelize the Onions: In a skillet over medium heat, melt the butter. Add the sliced onions, a pinch of salt, and cook until they are soft and caramelized, about 10-12 minutes. Stir occasionally to prevent burning.

2. Season the Beef: In a bowl, combine the ground beef with Worcestershire sauce, salt, and pepper. Mix gently to combine without overworking the meat.

3. Preheat the Skillet or Grill: Heat a cast-iron skillet or grill over medium-high heat until hot. This will give the burgers a nice sear.

4. Form the Patties: Divide the seasoned beef into four equal portions. Roll each portion into a loose ball. Do not overwork the meat.

5. Smash the Patties: Place each ball onto the hot skillet or grill. Using a spatula, press down firmly to flatten the patties into thick burgers. Cook for about 2-3 minutes without moving them.

6. Add Cheese: Once the patties have developed a nice crust, flip them gently and place a slice of cheese on each patty. Allow the cheese to melt as the burgers cook for an additional 2-3 minutes.

7. Toast the Buns: While the burgers are finishing, lightly toast the hamburger buns on a separate skillet or on the grill until golden brown.

8. Assemble the Burgers: On the bottom half of each toasted bun, place a smashburger patty piled high with caramelized onions. Top with the other half of the bun.

9. Serve Immediately: Remove from heat and prepare to serve.