Preheat the oven to 220C/425F/Gas 7. Flake
the fish into a bowl and stir together with the mashed potato, dill
and seasoning.
Shape into 8 rounds, dip in the beaten egg
yolks and sprinkle with breadcrumbs. Arrange on a baking sheet,
drizzle with a little olive oil and bake for 15-20 minutes, or until
heated through and crispy on the outside.
Combine the yoghurt and chives, and season to taste with salt and
pepper. Serve the fish cakes hot with the yoghurt dip, a rocket salad
and some lemon
wedges.