Place mustard, salmon, anchovies, yogurt, mayonnaise and juice in a blender and beat until smooth. Strain the resulting sauce.
Scald the tomatoes with boiling water, peel, salt, sprinkle with powdered sugar and put in the oven for 4 hours at a temperature of 70 degrees.
Salt and pepper the squid and shrimp and grill them. Lettuce and turnip cut into strips, season with sauce and put on a plate.
Lay shrimp and squid on top. Arrange the tomatoes on the sides of the plate.