In a 3-quart baking dish heat the oil over moderately-high heat until it is hot but not smoking and in it brown the lamb, patted dry, in batches, transferring it with a slotted spoon as it is browned to a bowl. In the fat remaining in the dish cook the onion over moderately-low heat, stirring occasionally, until it is softened, add the garlic, and the ginger root, and cook the mixture, stirring occasionally, for 3 minutes. Add the cumin, coriander, and flour, and cook the mixture, stirring, for 3 minutes. Add the stock, combined with 1 cup water, heated, whisking, and simmer the mixture for 5 minutes. Add the lime juice, the chilies, the tomatoes, the lamb and any juices that have accumulated in the bowl, and salt and pepper to taste and simmer the mixture, covered, skimming it occasionally, for 1 hour and 30 minutes, or until the lamb is tender.
While the mixture is simmering, in a large saucepan steam the spinach in the water clinging to the leaves, covered, over moderately-high heat, stirring occasionally, for 2 to 3 minutes, or until it is just wilted. Drain the spinach in a colander, refresh it under cold water, and squeeze it dry in a kitchen towel. Add the cauliflower to the lamb mixture, simmer the mixture for 5 minutes, and stir in the spinach. The stew may be prepared up to this point, cooled to room temperature, and kept covered well and frozen for up to 2 weeks. Let the stew thaw, covered, in the refrigerator before continuing with the recipe.
Bake the potatoes in a preheated 425 degrees oven, pricking them several times with a fork after 30 minutes, for 1 hour, or until they are very tender, and let them stand until they are cool enough to be handled. Peel the potatoes, force them through a food mill fitted with the medium disk over a bowl, and stir in the butter and salt and pepper to taste. Transfer the mixture to a pastry bag fitted with a large decorative tip and pipe it into 2-inch rosettes around the edge of the baking dish. The stew may be prepared up to this point, cooled to room temperature, and kept covered and chilled for up to 3 days.
Bake the stew in a preheated 400 degree oven for 20 to 30 minutes, or until it is heated through and the rosettes are browned lightly.
This recipe yields 6 servings.