Preheat the oven to 450 degrees F. Place a roasting rack on a foil-lined baking sheet in the oven.
Using your hands, break the meat into small pieces and combine evenly but loosely on a parchment or waxed paper-lined baking sheet. Spread the meat out and season it generously with salt and pepper. If desired, add the spice mix at this time.
Divide the meat into 4 portions (about 6 ounces each). Using your hands, form each portion into a ball-shape by gently tossing it from 1 hand to the other. (Don't over work or press too firmly on the meat.) Gently form each portion into a patty about 3 1/2 inches wide and 1-inch-thick.
Preheat a large cast iron skillet over medium-low heat for 5 minutes. Raise the heat to high and add the oil. Add the patties and cook, turning once, until well-browned, about 2 minutes each side.
Using a spatula, transfer the hamburgers to the roasting rack in the oven and continue cooking to desired doneness, 8 to 9 minutes for medium-rare, 10 to 11 minutes for medium, and 13 to 15 minutes for well-done. If you are using the cheese, top the hamburgers during their last couple of minutes of cooking to melt.
Transfer the hamburgers to a plate, let rest for a couple minutes before serving. Meanwhile, toast the hamburger buns. Assemble the hamburgers with the condiments and toppings of your choice. Serve.
When cooking on a countertop grill, turn on grill, then place burgers on the heated grill.
Timing for a countertop grill:
For Medium-Rare: Cook for 3 minutes covered and then unplug the machine and continue to cook covered for 2 to 3 more minutes.
For Medium: Cook for 4 minutes covered and then unplug the machine and continue to cook covered for 4 more minutes.
For Well: Cook for 5 minutes covered and then unplug the machine and continue to cook covered for 5 more minutes.