Preheat the oven to 400 degrees. Cook the tater tots according to the directions on the package or if making your own refer to the recipe in the menu.
Mix together the ground beef, steak seasoning, and Worcestershire sauce. Form into even patties.
Preheat a skillet or grill over medium heat. Grill the onion slices until golden brown on both sides. Then set aside.
Once hot, grill or cook burgers on both sides getting a nice crusty char to desired doneness (see below) using a thermometer. When the burger is 3/4 of the way cooked to your liking, add the cheese and melt.
Lightly toast the buns.
Top the burger with grilled onion, spring mix, and tomato. Serve with pickle and ketchup or your choice of condiments. Serve with tater tots.