||Heat the oil in a deep, nonstick skillet set over medium-high heat. Season the chicken evenly with salt and pepper. Cook chicken for 3 minutes per side or until browned; transfer to a plate.
TIP: To crush the peanuts, place them in a food processor and pulse until the nuts are so finely chopped they're almost a paste.
Fish sauce is prepared from fermented anchovies and salt, and is commonly used in Thai and Vietnamese cuisine. If unavailable, it can be replaced with soy sauce. Fish sauce can typically be found in the Asian section of most grocery stores and is inexpensive. It has a strong aroma but provides excellent savory flavor.
||Stir in the potatoes, onion, curry paste, fish sauce and ginger. Pour in the chicken stock and coconut milk; bring to a boil. Stir in the peanuts, cinnamon stick and bay leaf. Add the chicken back to the skillet.
||Reduce the heat and simmer for 30 minutes or until the potatoes are cooked through and the sauce is thick; discard bay leaf. Sprinkle with cilantro before serving.