For this recipe I like to use a griddle, it is important for the juices to float away from the burger while cooking. If you do not have one, you can use a very large skillet.
Preheat the griddle to 375 degrees. Hydrate the onions with warm water (about 1 tablespoon). Form 8 small round patties with the ground chuck. Place the patties on the hot grill. Use a spatula and press the patty into the grill for 4 to 5 seconds to sear in the juices. You know you have pressed the patty into the grill hard enough when you have to scrape it from the griddle. Season the patties liberally. Cook the patties on both sides. When you flip the burger, season the other side well.
When the burgers are done place the buns on the hot griddle and toast the buns until they begin to brown.
To assemble the burgers you will want to place 5 small squirts of mustard on the bottom bun. Follow the mustard with 5 larger squirts of ketchup. Add some onions, and a dill pickle slice or two. Place the hamburger patty on top of the pickle. Place the top bun on top of meat patty.