Preheat the oven to 425F. Line a baking sheet with tin foil, and set a rack in the lined sheet for cooking.
In a bowl, combine the lamb, cinnamon, cumin, allspice, olive oil, and mint with a sprinkle of salt. Grate the onion and garlic directly into the bowl, and mix the lamb mixture together evenly with your hands.
Form into golf-ball sized meatballs with your hands, then bake for 15 - 20 minutes until the meatballs are just barely still cooked in the center.
Serve as desired.
Notes
To make-ahead, you can half-bake the meatballs then refrigerate or freeze them until you're ready to use them. To bake from frozen, put the meatballs on a baking sheet or rack in the oven, THEN turn on the oven so the meatballs can heat through gradually as the oven heats up, then finish baking until cooked through.