1. In a medium bowl, sift together the flour, salt, sugar and baking soda.
2. In a separate bowl, combine the mashed sweet potato, oil, eggs, water and spices.
3. Using a wire whisk, gently combine the flour mixture into the sweet potato mixture, being careful to not over work. Stir in the nuts.
4. Spoon batter into 12 muffin cups. Bake in preheated 350 degree oven for 25 to 30 minutes, or until a wooden pick inserted in center comes out clean.