In a small bowl, whisk together the Dijon mustard, honey, olive oil, minced garlic, lemon juice, dried thyme, salt, and pepper until well combined. This will be your marinade and sauce for the chicken.

Place the chicken breasts in a resealable plastic bag or shallow dish, and pour the marinade over the chicken, making sure each piece is evenly coated. Seal the bag or cover the dish, and marinate the chicken in the refrigerator for at least 30 minutes, or up to 4 hours for maximum flavor.

Preheat your grill to medium-high heat. Remove the chicken breasts from the marinade, shaking off any excess, and discard the remaining marinade.

Grill the chicken breasts for 6-8 minutes per side, or until they are cooked through and have nice grill marks. The internal temperature of the chicken should reach 165°F (75°C) when fully cooked.

Once the chicken is cooked through, remove it from the grill and transfer it to a serving platter. Allow the chicken to rest for a few minutes before serving to allow the juices to redistribute.

Optionally, garnish the grilled chicken breasts with fresh parsley or chives for a pop of color and added freshness.

Serve the Honey Mustard Grilled Chicken Breast hot, alongside your favorite side dishes such as grilled vegetables, rice, or a crisp salad.

Enjoy your delicious and flavorful grilled chicken with honey mustard marinade!