1.   Butter one side of a square of foil to fit inside tart and place it, buttered side down, on pastry.

2.   Coat the buttered side of the fish with the sesame seeds.

3.   Place a slice of salmon on each buttered side of bread, then drizzle with sauce and add a cilantro sprig.

4.   Spread a thin layer of soft butter on one side only of both bread slices, then cover buttered sides neatly with a layer of cheese.