Make meat mixture. Work meats and spices together but do not overmix or the meat will get tough.
Form balls approximately 7 oz in weight. Flatten slightly in to a disk.
Use a beer can or bottle (I used a Corona bottle) to make an indentation in the ceter of the disk.
Layer the fillings you have chosen - about ½ tablespoon each in to the center of the indentation. You should be able to fit about 3 fillings. Gently fold the outer edges up and over the fillings. Pat with your hands gently so you don't see any of the fillings. Flatten in to disc-like patties. They will be thick.Optional: Refrigerate patties for 30 minutes or overnight. This can help the patties and fillings set.
When ready to cook, heat up the BBQ grill. Grill about 9 minutes over medium high heat on each side. Internal temperature should reach 160° F. (Check close to the center - you are trying to measure the meat clsoest to the center -not the fillings.)
Remove burgers from the grill. Cover loosely and allow to rest about 5 minutes.
Serve with buns and condiments of your choice.
Notes
Nutrition includes cheese, bacon, onion and mushroom fillings.