The onions will also add moisture to the meat. So mix those, the garlic and the steak spice in. One and a half pounds will make 4 perfect burgers.
Split evenly and form into patties about 4 inches wide. Or if you prefer thicker, make them about 3 inches wide. Get a spoon or something round. Press the center of the burgers down so that you don't get that humpy homemade burger syndrome happening.
Cook on the BBQ until they are done, and serve. You can top with whatever you want, but this Cajun type burger is so amazing. I didn't have any but I think a jalapeno Havarti would just about make this perfect.