Melt a tablespoon of salted butter in a skillet over medium heat. Toast hoagie rolls cut-side down for 2-3 minutes until golden brown and crispy. Set aside.

Add another tablespoon of butter to the skillet and sauté chopped onion for 4-5 minutes until soft and semi-translucent. Set aside.

Increase heat to medium-high, divide ground beef into four logs, season with salt, pepper, and garlic powder. Sear for 2 minutes, then flip and flatten into patties, cooking for another 2-3 minutes until browned.

Mix sautéed onions back into the skillet with beef, create a well for each patty and place two slices of American cheese on top. Cover to melt cheese for 1 minute.

Spread mayonnaise on toasted sides of hoagie rolls, scoop the beef and onion mixture onto the rolls, and top with tomato slices and shredded lettuce.

Wrap the sandwich in deli paper or serve whole. Cut in half if desired. Enjoy!