Place the trout, mayonnaise, lemon zest, salt, pepper and herbs in a bowl and mix to combine. Spread one side of each piece of bread with mayonnaise. Spoon 1 tablespoon of mixture into the centre of the bread and top with another slice of bread. Repeat with remaining bread. Using a sharp knife remove crusts and discard. Gently press down around the edges to seal. Cut in half to serve. Makes 6.