Lay out the oysters individually (flat side up) on a cloth and chopping board and cover with the cloth. Hold the oysters firmly, insert the tip of an oyster knife into the small opening at the hinge.
Open the upper shell with a sharp twist.
Slide the knife along the top side of the shell and prise open. The closed oyster must display considerable resistance to being opened, otherwise it will be inedible.
Remove the flesh, set aside. Mix the mascarpone with all the other ingredients up to and including the pepper. Place the bottom half of the shells in an ovenproof dish, spoon the mascarpone mixture into the shells. Place the oyster flesh on top, cover with the remainder of the sauce. Approx. 10 mins. in the centre of an oven preheated to 200°C. Garnish with dill.