1 Preheat oven to 375°F Heat 2 Tbsp olive oil in a large sauté pan on high or medium high heat (hot enough to brown but not burn). Sprinkle a little salt on the bottom of the pan. Sprinkle salt and pepper all over the chicken pieces. Working in batches, brown the chicken pieces on 2 sides, about 1-2 minutes per batch. Add a little more salt (and more olive oil if needed) after every batch. This will help prevent sticking. Remove chicken pieces and set aside in a bowl. Note that the chicken does not have to be cooked through, only browned.
2 In the same pan add 1 tablespoon olive oil, lower the heat to medium, add the onions, and cook until translucent, about 3 minutes. Add the garlic, cook 30 seconds more. Remove onions and garlic to a shallow casserole dish (9x13x2).
3 Raise heat to medium high, add the sliced mushrooms. Dry sauté them (no need to add oil or butter), allowing them to brown lightly, and release some of their moisture. Add the mushrooms to the casserole dish.
4 Deglaze the pan with 1/4 cup dry sherry or dry white wine. (At this point, if you are making ahead, reduce the sherry to 1 Tbsp and pour off into the casserole dish. Refrigerate cooked onions, garlic, mushrooms, and browned chicken pieces until you are ready to make the casserole.) Let the sherry reduce to about 1 Tbsp, then add the chicken stock, and remove from heat. Stir in 1 1/2 teaspoon salt, the cream, and the sour cream. Add the raw rice to the casserole dish. Then pour the stock, cream, sour cream, sherry mixture over the rice. Add the poultry and Italian seasonings (or fresh herbs) and paprika to the dish. Stir the rice, mushrooms, onion, herb mixture so that they are evenly distributed in the casserole dish.
5 Place the chicken pieces on top of the rice mixture (in a single layer if you can, they will be crowded together). Cover tightly with aluminum foil. Bake in 375°F oven for 45 minutes. Remove foil. If the casserole is too liquidy, let it cook several minutes more uncovered, until the excess liquid has evaporated away.
Sprinkle with fresh parsley before serving.
Serves 6 (with leftovers).