Place the chicken breasts between two layers of parchment/baking paper and flatten out slightly with a meat mallet/rolling pin.
Whisk together the marinade ingredients.
Place the chicken in a glass container and pour over the marinade. Mix to make sure the chicken is well-coated then cover and allow to marinade for at least 20 minutes but up to 24 hours, refrigerated.
To cook the chicken breasts, heat a skillet, pan or grill then add the chicken and cook for 3-5 minutes per side (depending on thickness) until cooked through but still juicy.
Remove from the heat and cover with foil, allowing the chicken to rest for at 5-10 minutes before serving.