Reserve 1/2 of the marinade ingredients; simmer in a pan until thickened into a syrup.
Marinate chicken in the other 1/2 of the mixture for 1–2 hours.
Preheat grill to medium-high.
Grill chicken for 5–6 mins per side; brush with thickened glaze in the last 2 mins.
Grill pineapple rings for 2 mins per side until charred.
Serve chicken topped with pineapple and fresh cilantro.
Notes
Discard marinade that touched raw chicken.Pounding the chicken ensures it cooks at the same rate as the fruit.Add a squeeze of fresh lime at the very end to cut through the sweetness.Great for meal prep as the chicken stays moist.