1/ Blitz the chicken breasts, season and add the egg white. Blitz again until smooth. Slowly add the cream and Périgord walnuts. Season to taste with curry powder and chopped coriander.
2/ Put a slice of bread in a cake tin and gently spread the chicken mousse on top. Top with a second slice of bread.
3/ Cover with cling film. Cook in a bain marie for half an hour at 90°C. Leave to cool and slice into bite-size pieces.
4/ Whisk the yoghurt, olive oil and chopped coriander. Season and garnish with curry powder.
5/ Toast the sandwiches on both sides. Serve with the yoghurt sauce.
By Chef Vincent Arnould