Step 1

Combine cilantro, lime juice, olive oil, mustard, cumin, garlic powder, and chipotle in a medium bowl.

Step 2

Set chicken on a work surface with the smooth side up. With the heel of your hand or a meat mallet, lightly pound the thick portion of each chicken breast piece so the whole breast is an even 1 inch thick. Add chicken to bowl of marinade and turn to coat. Cover and refrigerate 1 to 4 hours.

Step 3

Preheat a grill for medium heat (350°F to 450°F). Set chicken on a plate and let stand at room temperature 20 minutes. Season chicken with salt and pepper. Following the insertion guide on the Yummly Thermometer app, insert the thermometer horizontally into a chicken breast until the metal is completely covered.

Step 4

Grill chicken with the smooth side down for 3 minutes with the lid closed. Rotate chicken 1/4 turn (this will give you those nice grill marks). Close the lid and grill 2 minutes longer. Turn chicken over (or flip when directed to by the Yummly Thermometer app) and grill until the temperature reaches 160°F, 5-10 minutes longer. Transfer to a cutting board and let rest 5 minutes before serving.