Shape beef into 4 patties about 1/4" thick (I made mine square to fit my bread hehe). Sprinkle both sides of each patty with desired amount of your favorite burger seasoning.

Heat a skillet over medium heat. Add about 2 tsp oil to help prevent sticking. When hot add burger patties. Cook until first side is browned, about 2-3 minutes. Flip patties. Place 2 slices of cheese on each patty.

Turn heat down to low. Place lid on skillet. Continue cooking until cheese is melted, about another 2-3 minutes (yes, that will be enough to cook the burgers through).

While patties finish cooking mix mayo, horseradish, and ketchup in a small bowl and toast your bread. Plate toast. Spread a little sauce on each piece of toast. Place patty on top, cheesy side up. Enjoy!