1. Cut a disc of puff pastry into 8 slices.
2. Roll up the slices starting from the base of the triangle and curving them like a croissant.
3. Brush the croissants with egg yolk beaten with a spoonful of milk and arrange them on a tray lined with baking paper.
4. Place in the oven at 180°C for 15 minutes.
5. When cool, cut in half lengthwise and cover lightly with mayonnaise.
6. Place the drained and coarsely chopped La Croccante on the lower half.
7. Cut the smoked swordfish into fairly thick slices and place them in each croissant.
8. Garnish with lettuce leaves.