Place 4 eggs in a pan and cover with cold water.
Add 5 ml (1 tea spoon) salt and bring to the boil.
Reduce the heat and simmer for 8 minutes.
Cool the hard-boiled eggs under running cold water and then remove the shells.
Finely chop the eggs and mix them with 150 ml (1/4 pint) (5/8 cup) mayonnaise, 10 ml (2 teaspoons) made mustard, one finely chopped small onion, and seasoning to taste.
Spread the mixture over halved bridge rolls and garn- ish each roll with an anchovy fillet and a halved black olive, or three capers arranged in a row and a sprig of cress.