- Cook chicken in oil in Dutch oven over medium-high heat until brown, about 8 minutes.
- Remove chicken; set aside.
- Cook white part of leek until soft over medium-high heat, about 2 minutes.
- Add chicken broth and rice; bring to a boil.
- Reduce heat to medium and cook uncovered 10 minutes, stirring frequently.
- Add chicken; cook 5 minutes.
- Stir in brie, cream, salt and pepper.
- Stir until creamy and cheese is melted, about 4 minutes.
- Garnish with green part of leek, if desired.