Start by preheating a cast iron skillet on medium, to medium high heat.

During this time, form the ground chuck into a loose meatball shape. Season with a bit of salt and pepper, to your liking.

Add the ground chuck to the cast iron skillet, and let it sear, and cook for a couple of minutes. Then, with a large spatula smash the burger down, completely flattening it. Let cook another minute, then flip it over. You should have an awesome, caramelized burger. Season with a pinch of salt and pepper, then add the thinly sliced onions over the top of the burger, letting the burger steam the onions. After a couple of minutes, flip the burger, along with the onions, over, allowing the onions to cook.

Add the Merkts cheese on top of the burger and allow that to begin to melt.

Place the burger onto the bun, and serve.