Step 1

Prepare the mayonnaise: In a medium mixing bowl, whisk together the egg yolk and Dijon mustard until slightly thick and smooth. Nestle the mixing bowl in a twisted and rounded kitchen linen to prevent it from slipping and moving on your countertop. Slowly pour the oil in a very, very thin stream – think droplets at at time at the beginning – into the egg yolk mixture while whisking continuously and aggressively with your other hand. Your arms should burn a little. You want to use a flexible large whisk, not a stiff whisk, otherwise your ingredients may not emulsify properly. The mayonnaise will be very thick. Slowly whisk in the lemon juice until smooth. The mayonnaise should be smooth, thick, and pale yellow in color. Season to taste with cayenne pepper, kosher salt, and black pepper. Set aside until ready to use. Homemade mayonnaise can be stored in an airtight container in the refriegerator for up to a week.

Step 2

Prepare egg salad: Place the eggs in a medium saucepan and add cold water, until the water reaches about an inch above the eggs. Bring to a rolling boil, remove from the heat immediately, and set your kitchen timer for 10 minutes. This will produce an egg with a firm white and cooked, but still slightly moist egg yolk. If you prefer slightly gooey yolks, reduce the time to 9 minutes. If you prefer very dry yolks, increase the time to 11 minutes or more.

Step 3

As the eggs are cooking, set up an ice bath. Once the eggs have finished cooking, transfer them gently to the ice water with a slotted spoon. Allow the eggs to cool until they can easily be handled – about 5 to 10 minutes.

Step 4

To peel: Remove one egg at a time from the ice water and gently tap it all over on your kitchen countertop to gently break the egg shell all over. Place the egg back into the ice bath and gently peel it, dipping it back into the ice water continuously – this will make it much easier to peel. Slice the eggs in half and transfer to a medium mixing or serving bowl, and repeat until all the eggs are peeled.

Step 5

Add ½ cup homemade mayonnaise to the bowl and using a fork, gently mash the eggs and mayonnaise together until incorporated evenly. I prefer a slightly chunky egg salad with good texture, as opposed to a very fine egg salad texture, but adjust this to your liking. Gently stir in 1 tablespoon sliced chives. Season to taste with salt and pepper (or more cayenne pepper, if desired).

Step 6

Assemble sandwiches: *If using a nice artisanal loaf of bread, I prefer to slice the bread slices in half, rather than assembling and trying to cut a sandwich in half. It prevents the egg salad from spilling out the sides. Place a small handful of watercress on the bottom half of each bread slice, top with a generous spoonful of egg salad. Top with a few more watercress leaves and the top half piece of bread. Gently press or sprinkle any remaining chopped chives onto any exposed egg salad on the sides of the sandwich. Serve immediately.