1. Have ready a baking dish with a 6-cup capacity. Pat the chicken pieces dry with a paper towel and sprinkle them lightly with salt and pepper. In a large skillet, heat the ghee or oil over medium-high heat for 1 minute. Add the chicken pieces and use tongs to turn the chicken once to lightly brown on both sides, about 5 minutes. The chicken is not fully cooked at this point. Remove the chicken to a clean plate and set aside.
2. Reduce the heat to medium and add the onions, garlic, and ginger to the skillet. Cook until the onions soften and the edges begin to brown, about 6 minutes, stirring often. Stir in the cumin, coriander, curry powder, and cayenne or paprika, stirring to blend the spices. Add the tomatoes and use a fork to break them up into pieces about ¾ inch in size. Pour in the water and return the chicken and any accumulated juices to the pan. Cover and cook on low heat at a gentle simmer, stirring occasionally, until the chicken pieces are no longer pink in the center, about 20 minutes.
3. Remove the pan from the heat and remove the ginger slices and discard them. Put the yogurt and cream in a small bowl and whisk in about ½, cup of the warm liquid from the pan. Stir the yogurt mixture into the chicken curry to blend it into the sauce. Taste the sauce and add additional curry powder, if desired. Transfer the filling to the baking dish and let it cool for about 15 minutes while you roll the crust. Or, cover the filling with plastic wrap and refrigerate it for up to 1 day.
4. Position a rack in the middle of the oven. Preheat the oven to 375°F.
5. Lightly flour the rolling surface and rolling pin. Roll the crust dough to a shape that is 1 inch larger than the top of the baking dish. Roll the crust around the rolling pin and unroll it over the cooled chicken filling. Fold ½, inch of the edge of the crust under to form a smooth edge. Use fork tines to press the dough firmly onto the rim of the baking dish. Cut four 2-inch-long slits in the top of the crust to release steam while the pie bakes.
6. Bake for about 30 minutes, or until the crust is lightly browned. Let rest for 5 minutes, then use a large spoon to cut down through the crust and scoop out servings of crust and filling. Sprinkle with the cilantro and serve.