In a large zip top bag, combine the yogurt, ground almonds, spices, ginger, garlic, tomatoes and salt. Add the chicken, press out as much air as possible and seal the bag. Refrigerate 2-4 hours.
Melt the butter and oil in your wok or saute pan. Saute the onions over medium heat until soft and translucent, about 3 minutes. Add the chicken mixture, including all the marinade. Bring to a boil over medium-high heat, then reduce to a simmer for about 10 minutes, or until chicken is cooked through. Add half the cilantro.
Pour in the half-and-half and stir well. Bring to a boil, then immediately switch off heat. Serve garnished with the remaining chopped cilantro and sprigs.