Cut the garlic in thin slivers, and thinly slice the truffle or cut the porcini into thin slivers. Ease the skin away from the flesh of the turkey, over breast, thighs and drumsticks. Arrange the garlic, truffle or mushroom pieces and the herbs over the flesh. Draw the skin back into place and secure with a cocktail stick.
Mix the port or sherry and olive oil or butter, and brush it ove