Mix all ingredients together with hands, excluding sandwich thins. Form into 8 patties with even size and thickness.
Grill: Oil the grill. Place patties on hottest oiled parts of grill; sear until browned, 1 to 2 minutes per side. Move patties to cooler part of grill; continue grilling until cooked through, 5 to 10 minutes per side.
Stovetop: Place into a lightly greased non-stick skillet (a cast-iron skillet is perfect) on medium to medium-high heat. Cook without moving until bottom side is golden brown, about 4-5 minutes. Turn patties over and reduce heat to medium-low, cover pan and cook 4-5 minutes longer until juices run clear.
Optional ingredients: Add a couple tablespoons of your favorite left-over chopped herbs to the burger mixture (e.g., basil, parsley, tarragon, sage)