Step 1

In a medium bowl, gently mix together the ground chuck, short rib, and brisket with 2 teaspoons salt and 1 teaspoon ground pepper.

Step 2

Shape the meat into 4 equal patties about 4½ inches wide and 1 inch thick. Use your thumb to press an indentation into the center of each patty to prevent a bubble from forming in the center when cooking. Generously season the tops and sides of the patties with salt and pepper.

Step 3

Heat a large cast iron skillet over medium heat. Spread about ½ tablespoon of butter onto each cut side of the hamburger buns. Working in batches, toast the buns, buttered-side down, for about 2 minutes, until golden brown. Set aside.

Step 4

Increase the heat to medium-high. Add a thin layer of canola oil to the pan and cook the burgers for 4 minutes on one side, until nicely browned. Flip and cook for another 2 minutes on the other side. Top each burger with a slice of cheese and cover the pan with a lid. Cook until the cheese is melted and the internal temperature of the burgers reaches 135°F (57°C), another 1–2 minutes.

Step 5

Assemble the burgers: Place a burger patty on each toasted bun, then top with a slice of tomato and red onion, lettuce, ketchup, mayonnaise, and mustard. Serve immediately.

Step 6

Enjoy!