Preheat an oven to 400ºF.
In a large mixing bowl, combine the sirloin, grill seasoning, allspice, grated onion and spaghetti. Work the mixture together with your hands until well combined. Roll mixture into meatballs slightly larger than a golf ball and arrange them on a baking sheet. Drizzle with about 2 tablespoons EVOO and pop into the oven. Bake until deep golden brown and cooked through, 15-18 minutes.