• 6 eggs
  • 1/2 cup finely chopped fresh chives
  • 2 tablespoons finely chopped celery leaves
  • salt & freshly ground black pepper
  • 1/3 cup mayonnaise
  • 2 teaspoons white wine vinegar
  • 2 teaspoons Dijon mustard
  • 4 slices pumpernickel bread
  • 1 1/2 tablespoons butter , softened
  • 1 bunch watercress , stems trimmed
  • 1 Arrange eggs in a single layer in medium pot and cover with cold water by 1”. Bring to a boil over medium-high heat, then immediately remove pot from heat. Cover and let rest for 8-10 minutes undisturbed.
  • 2 Drain eggs, leaving them in the pot; shake the pot to crack their shells. Cover eggs with cold water, swish around, then drain. Cover again, this time with icy-cold water (add a few ice cubes if necessary), and set aside to let chill for 20 minutes. Peel and coarsely chop eggs.
  • 3 Combine eggs, half the chives, celery leaves and salt and pepper to taste in a medium bowl and fold together gently to combine. Add mayonnaise, vinegar and mustard and fold again, being careful not to mash up the eggs.
  • 4 Toast bread lightly, then butter each slice on one side. Arrange a bit of the watercress on top of each piece of toast, buttered side up. Dollop each piece with a generous scoop of egg salad. Transfer the sandwiches to plates. Sprinkle with remaining chives and serve immediately.