Tempeh normally comes in a cube shape, so it's easiest to slice it into squares. Round off the corners if you prefer your burgers to have a round shape. Each slice should be 1/2 inch thick. Use a nine or twelve-inch pan, depending on which size is large enough to hold all the pieces in a single layer.  In a small bow, whisk the soy sauce, olive oil, brown sugar, and thyme. Make sure each slice gets covered in plenty of marinade. During this time the marinade will begin to flavor and soften the tempeh. By the time you are finished baking the tempeh, all the marinade should be absorbed. If you still see liquid in the pan, keep baking the tempeh until the liquid is absorbed. Use a spatula to loosen the tempeh burgers from the pan. Place them on buns and serve with lettuce, tomatoes, and cheese.
Slice the tempeh into patties. Place the tempeh pieces in a baking pan. Preheat the oven to 375 °F (191 °C). Mix up the marinade. Pour the marinade over the tempeh slices. Bake the tempeh for 30 minutes. Flip the tempeh and bake for another 30 minutes. Remove the pan from the oven. Serve the tempeh burgers.