Preheat the oven to 180C.
Cut the chicken into bite-sized pieces. Heat the oil in a heavy-based casserole dish with a tight-fitting lid. Season chicken with salt and pepper and cook until starting to colour. Remove and set aside.
Cut the carrots and leek into rounds and sautee in the chicken pan until beginning to soften - 2-3 minutes
Add the garlic, thyme, and bay leaves to the dish and give it a quick stir. Add the chilli or smoked paprika, lemon zest and juice and season with salt and pepper.
Add the chicken back to the pan, pour in the cold water, turn up the heat and bring the liquid to the boil. Once boiling, cover with the lid, place in the oven and bake for 15 minutes. Take the dish out of the oven. Stir the orzo into the liquid around the chicken. Return the uncovered dish to the oven and bake for another 15 minutes or until the orzo is al dente. Allow the dish to set aside for 10 minutes covered so the orzo can soak up the tasty cooking liquid.
Check the seasoning once it is cooked and stir in the fresh parsley.