Toast the sesame seeds in a hot, dry pan until they turn a pale golden colour. Set aside.
Heat the butter and olive oil in the pan. Add the chicken fillets and fry for 5 to 7 minutes on each side, until cooked through. Remove from the pan and keep warm.
Add the orange juice, tarragon and honey to the pan. Stir well over a low heat.
Pour the sauce over the chicken and scatter the toasted sesame seeds on top.