Season the turkey steaks and brush with olive oil.
To make the spice marinade, mix together all ingredients. Rub this mixture all over the turkey, patting in well. Place in a dish, cover and chill for about 1 hour. Meanwhile light the bbq.
Whilst the bbq is warming up, place the rhubarb, ginger, lemon grass and sugar into a pan and cook over a low heat until thick and well cooked. Liquidise to a puree. Divide the rhubarb puree in half, spooning some over the turkey breasts and reserve the other half to use as a dip.
When the bbq is hot and the coals have turned grey, cook the turkey breasts carefully on both sides for about 6-9 minutes, basting frequently with the rhubarb glaze. Test the breasts are cooked through with a sharp knife.
Serve with the reserved dipping sauce and a few boiled new potatoes and watercress salad.
© Phil Vickery