Mix all ingredients for sauce in a small saucepan. Cook on low heat until bubbly and thick. Brush the plums on cuts side with sauce, and set aside.
Pound chicken breasts to achieve even thickness.
Brush the grill with olive oil and grill chicken breasts for approximately 4 minutes on each side until you have achieved nice grill marks.
Move to the other side of the grill. Let the chicken indirect grill until it reaches 165° F (Approximately 45 minutes, depending on the thickness). Remove the chicken and let it rest. While the chicken is resting, grill the plums for approximately two minutes on each side to get nice grill marks.
Serve with rice pilaf and your choice of vegetables. Serve with extra sauce spooned on top.
Notes
Put the sauce on in the last 15 minutes of grilling to prevent burning.What to do with leftoversStore leftovers in an airtight container or storage bag for 3-4 days in the refrigerator.The chicken freezes well. This is a perfect meal prep recipe. Make a big batch, freeze it in airtight containers or freezer bags for up to 4 months. Freeze it in quantities suitable for feeding the family for one meal.Make sandwiches or salads with the leftover chicken. To reheat the chicken, cover it and grill or bake for 15-20 minutes until warmed through.