Preheat the oven to 325ºF and line a rimmed baking sheet with parchment paper.
Add the ground meat to a large bowl. Grate the onion on the large holes of a grater right into the bowl. Add the garlic, marjoram, cumin, salt, and pepper.
Use your hands to work the ingredients together, squeezing the meat together really well. Form into a long flat loaf, about 4 by 10 inches.
Bake 30 to 40 minutes, or until the center of the loaf reaches 160ºF on an instant read thermometer. Let cool completely.
Use a sharp knife to slice the loaf into thin slices, no thicker than ¼ inch. Add a small amount of oil to a pan over medium high heat and sear the slices quickly on each side, about 1 minute.