Cut the brick pastry sheets into bands approximately 8cm wide. Lightly brush with melted butter.
Thinly chop the basil leaves, cut a slice of smoked trout into small cubes and mix it all with the cheese. Season with salt and pepper to taste.
At one end of each band, place half a slice of smoked trout and spread a teaspoon (or more) of the mixture on top and then shape the samosas into triangles.
Place the samosas on a baking tray lined with baking paper.