How to Make It
Light a grill or preheat a grill pan. Season the chicken breast liberally with salt and pepper. Grill the breasts over moderately high heat, turning occasionally, until the chicken is lightly charred and cooked through, 20 to 25 minutes. Transfer the chicken to a work surface and let rest for 5 minutes.
Meanwhile, puree the chipotles in a blender or food processor until fairly smooth, adding adobo sauce as needed to loosen. Serve the chicken with the adobo sauce on the side.
Chipotles in adobo can be found at Mexican markets, natural food stores and gourmet markets.