How to Make It
Heat oil in a large skillet over medium-high. Add chicken, and cook until well browned, about 5 minutes. Turn chicken over, and cook 2 minutes.
Transfer chicken to a 5- to 6-quart slow cooker. Add celery, onion, and garlic to skillet. Cook, stirring often, until starting to soften, about 4 minutes. Add flour to skillet, and cook, stirring constantly, 1 minute. Add broth; bring to a boil, and cook, stirring constantly, until thickened, about 1 minute.
Transfer mixture to slow cooker. Add pumpkin, rice, and salt. Cover and cook on LOW until rice, chicken, and vegetables are tender, about 3 hours.
Stir in half-and-half, parsley, tarragon, and thyme leaves.