1. In a small bowl, combine the pepper jelly and mustard; set aside. Season the chicken breasts on both sides with salt and pepper. In a large skillet, melt the butter over moderately high heat. When the foam subsides, add the chicken breasts and cook, turning once, until browned, about 3 minutes per side.
2. Tilt the skillet and pour off most of the fat. Add 1 tablespoon of water and shake the pan to loosen the browned bits on the bottom. Push the chicken to one side, add the celery matchsticks and cook, stirring, for 1 minute. Add the pepper jelly mixture and the lemon juice to the pan and shake to coat the chicken with the sauce. Cook until the sauce is reduced to a glaze, about 30 seconds. Season with salt and pepper.
3. Transfer the chicken to plates and spoon the celery matchsticks on top. Garnish with the celery leaves and serve at once.
Serve With: Fragrant rice and a fresh lima bean and corn succotash with basil.