1.Mix all of the above ingredients together and form into ¾ inch thick patties. Refrigerate covered with plastic wrap for 1 hour prior to grilling.
2.To prepare: Oil the grates of your grill and heat the grill to medium-high. Season the burgers liberally on both sides with additional blackened seasoning.
3.Place the burgers on the hot grill and grill to your desired level of doneness. For medium about 4 minutes on each side, for well done, around 6 minutes on each side or until the juices run clear. [depending on the thickness of the burger] Yield: 6-8 burgers
4.To make the onions: In a stove top pan, heat the oil and add the sliced onions. Season with salt and pepper to taste and allow to simmer on low heat for 15 minutes or until they start to brown. Add the balsamic vinegar, mix well.
5.Serve on top of the burgers.
The amount of grilling time for the burgers depends on how thick the burgers are made. If you prefer a well done burger make the burgers thinner making it easier to cook to well done. If a medium burger is your preference make the burger thicker, and cook accordingly.