Cook the onions in 2 tablespoons of the fat in a large wide pan over medium-high heat for about 8 minutes, until soft and translucent. Lower the heat if they begin to brown. Transfer to a bowl.
Cook the cauliflower rice in the remaining 1 tablespoon fat over medium heat for 8 minutes, until visible steam slows and no loose water remains. Lower the heat near the end if it begins sticking. Transfer to a bowl.
Preheat the oven to 350°F. Lightly grease a 9-by-13-inch baking dish with a permitted cooking fat.
Cook the ground beef and sea salt in the same pan over medium-high heat for about 5 minutes, breaking it into small crumbles, until most pink is gone.
Return the cauliflower rice. Add the ground ginger, cumin and optional garlic and pepper. Cook 2 to 3 minutes, until the beef has no remaining pink and the spices smell fragrant. Remove from the heat.
Blend the coconut aminos, meat stock, fresh ginger and 2 cups of the cooked onions on medium speed for 30 seconds, until completely smooth and about the thickness of applesauce.
Add the raw cabbage, remaining onions and blended sauce to the beef and cauliflower. Toss until every cabbage ribbon is coated; use a large bowl if the pan is too small.
Spread the mixture in the prepared baking dish and smooth the top gently without packing it down.
Bake for about 45 minutes, until the edges and center bubble, the cabbage is tender, the top is lightly browned and the center reaches 165°F.
Rest for about 10 minutes. Top with chopped fresh cilantro if using, then serve.