Place the chicken breast (one at a time) one a chopping board and cover with saran wrap (cling film).
Use a meat mallet or tenderiser to smash the chicken all over (this will help the chicken to cook quicker and tenderise it) repeat this step with the other fillets
Use a fork to prick the flesh of each piece of chicken
Place the chicken in a large bowl (or zip bag) and pour the marinade into over the chicken until it is completely covered. If you are using a zip lock bag, give it a good shake.
Cover (if using a bowl) and refrigerate for 4-6 hours
While the chicken is marinating, get your dressing ready by place it in a frying pan on medium heat and simmering for 2-3 minutes along with the maple syrup (if using).
Remove pan from the heat, once cool blitz the in a blender if you want a smooth dressing and set aside.
When ready to cook, remove from the fillets from the bowl/bag and discard the contents.
Preheat a grill, broiler, outdoor grill on high heat
Lightly spray your grill grates with oil
Add you chicken to the grill and reduce the heat to medium
Sear each side of the chicken (should take about 5-7) minutes until juices from clear (temp 165 F or 75 C)
Serve with the mojo dressing