Preheat the oven to 400° F.Cook the olive oil and onion in a large oven-safe skillet with sides, over medium heat, until fragrant, about 5 minutes. Push the onions to the side. Add the chicken and sprinkle with the curry powder. Season with salt and pepper. Add the butter, shallots, celery, carrots, thyme, and sage. Season again with salt and pepper. Cook another 5 minutes. Pour in the apple cider, 2-3 cups broth, and lemon juice. Add the garlic and parmesan rind. Transfer to the oven and cook uncovered for 15 minutes, until the chicken is cooked through. Pull the skillet out, add 1/2 cup of broth and the orzo. Return to the oven and cook 10-12 minutes, until the orzo is al dente. If you want more broth, add the remaining 1-2 1/2 cups.Serve the chicken over the orzo and broth. Top with parmesan (if desired), plus thyme or parsley.