Knife-and-Fork Egg Salad Sandwiches with Chives | Saveur

Ingredients

• 6 eggs
• ¹⁄₂ cup finely chopped chives
• 2 tbsp. finely chopped celery leaves
• Salt and freshly ground black pepper
• ¹⁄₃ cup mayonnaise
• 2 tsp. white wine vinegar
• 2 tsp. dijon mustard
• 4 large slices pumpernickel bread
• 1 ¹⁄₂ tbsp. butter, softened
• 1 small bunch watercress, stems trimmed