1Make Mustard and Maple Marinade: Place marinade ingredients in a medium bowl and whisk to combine. Add chicken and turn to coat. Put aside.
2Place sweet potato slices on a microwave-safe plate. Season with salt and pepper and pour over the stock. Cover plate with vented lid or plastic wrap and place on the turntable. Press MICROWAVE and set to 100% for 5 minutes. Press START to begin cooking.
3Arrange chicken slices in a single layer over sweet potatoes and place broccolini next to the chicken. Cover and place back on the turntable. Press MICROWAVE and set to 100% for 4 minutes. Press START to begin cooking.