1.Boil eggs in a medium saucepan of water for 6 minutes or until hard. Cool, then peel and coarsely mash eggs with a fork.
2. Combine egg, mayonnaise, mustard and herbs in a medium bowl. Season to taste.
3.Butter bread slices, sandwich egg mixture and watercress between bread slices. Discard crusts, cut each sandwich into four fingers.
Use a whole-egg mayonnaise as it has a creamy texture. Swap watercress for your favourite leafy green, rocket (arugula) or endive would both work well as they have a slightly bitter taste.Note