Place hash brown patties in a layer in a baking dish. Bake for about 25 minutes until crisp.

Finely mince 2 tablespoons of onion and set aside. Dice the remaining onion.

Mix minced onion, mayonnaise, 1/2 teaspoon salt, relish, vinegar, sugar, mustard, paprika, and onion powder in a bowl. Set aside.

Heat oil in a skillet over medium-high heat. Add ground beef and cook for 3 minutes. Crumble the meat while cooking until browned, around 5 minutes. Add remaining salt, pepper, Worcestershire sauce, and chopped onion, cooking for 1 more minute.

Stir in 2/3 cup of sauce mixture and 1 1/3 cup cheese.

Flip hash brown patties so crispy side is up. Pour meat mixture over hash browns and sprinkle remaining cheese on top.

Sprinkle with sesame seeds and bake until bubbly and melted, about 10-12 minutes. Let stand for 5 minutes.

Top with shredded lettuce, a drizzle of remaining sauce, and chopped pickles. Serve immediately.