- Dissolve tamarind paste in 1 cup water. Let stand 30 minutes. Strain. Boil potatoes until just tender. Cool completely, then peel. Using wooden skewer, pierce each Potato in 4 places.
- Heat oil in heavy large skillet over medium heat. Add Onion and cook until crisp and lightly browned, stirring frequently, about 10 minutes. Remove from skillet.
- Add potatoes and brown well on all sides. Remove from skillet. Pour off all but 1 tablespoon oil from skillet. Add ginger and garlic and stir 1 minute. Stir in pepper flakes and turmeric. Blend in 2 tablespoons water. Mix in Onion. Add potatoes, tamarind liquid and remaining 14 tablespoons water. Stir in cardamom, fennel, cinnamon and pepper.
- Cover and simmer until sauce has thickened slightly, about 15 minutes. Season with salt.