Preheat oven to 350°F. Spray a 9x13-inch casserole dish with nonstick cooking spray.
In a small bowl, whisk together the seasoned salt, hamburger seasoning, salt, and pepper.
Heat the oil in a large skillet. Add half of the diced onion, and the garlic. Cook for 1-2 minutes.
Add the ground beef to the pan. Break up the meat with a wooden spoon. Add the Worcestershire sauce and the seasoning mixture.
Cook for about 8-10 minutes, or until no pink remains in the meat. Remove from heat.
Stir in 1 cup of the shredded cheddar cheese, and 1 tablespoon ketchup.
Spoon the hamburger mixture evenly into cooked shells and place into the prepared casserole dish.
Top with remaining cheddar cheese.
Bake 15-20 minutes, or until bubbly.
Top with diced pickles, tomatoes, and onions (optional).