Recipe I would like to try: Smoked herring patê

Most of my recipe booklets live in folders and boxes that I rarely open, but most of them contain at least one recipe I would like to try. Here is one of them:

Patê brisée:
200 g flour
100 g butter
1 egg yolk
3 tbs water

Sauce:
200 g sour cream
100 g mayonnaise
4 tbs lemon juice
60 g chives
Salt and pepper

Patê:
500 g kippered (salted and smoked) herring
100 g onions
1 egg white
Salt and pepper
A dash of vinegar

Brisée pastry:
Mix flour, sugar and butter until the mixture forms fine crumbs. Add water and egg yolk and knead into a solid smooth mass. Refriegerate for several hours. Roll out and line a patê dish or other deep oven-proof dish with it.

Sauce:
Mix mayonnaise and sour cream until smooth. add finely chopped chives and lemon juice, salt and pepper.

Patê:
Grind together the herring and onion, either by running through a food grinder twice, or by processing on a food processor (use the blades). Mix in the egg white, spices and vinegar. Put into the brisée-clad dish and bake at 100°C for 60 to 90 minutes. Increase the temperature to 190°C for about 5-6 minutes at the end of the cooking time.