Preheat
oven to gas mark 4/180º C. Wash and dry salmon fillets and
cut into four rectangles. Sprinkle with lemon juice. Chop
mushrooms and onion roughly. Melt butter or margarine and
fry mushrooms and onion for about 5 minutes.
Add the
breadcrumbs. Separate one egg and mix the egg white into the
mixture. Spread the stuffing on the salmon fillets and roll
them up, securing them with wooden cocktail sticks.
Grease
an ovenproof dish and place the fish rolls upright, adding
any remaining stuffing around the rolls. Mix egg yolk, egg
and sour cream and season well with salt and pepper.
Pour
over the fish rolls and cook on the middle shelf for 30
minutes.
