Mix the ground sirloin, pepper, and seasoned salt in a bowl and combine thoroughly.
Heat a pan to medium-high heat. Slice the onions into very thin rings and place them in the pan with peanut oil. Allow the onions to grill slowly but make sure they don't become brown.
While the onions are cooking, form your hamburger patties and place them into the hot pan. Grill for 4 to 5 minutes on each side. Then remove the patties and the onions from the pan.
Open each mini bun, and add 1 mini patty, 2 pickles, a half a slice of cheese, grilled onions, a sliced tomato, and some ketchup. Add the top bun, serve hot, and enjoy.
