Place the eggs in a pot and cover with cold tap water, until there is about an inch over the eggs. Set burner to high and bring the water to a rolling boil. Once it reaches that point, you can reduce the heat to low-medium. Cook for an additional 10 minutes. Once cooked, immediately remove from heat and run cold water over them, or immerse in an ice bath until completely cooled.

Peel the eggs and place in a medium-sized bowl. Begin mashing the eggs until the salad is fairly chunky. Add in the dill, olive oil, mustard, and shallot, and continue mashing until it reaches your desired consistency. Set bowl aside and begin working on the leeks.

In a pan, add the butter and set the burner to medium high heat. Once the butter has melted, add the leek greens and cook for 5-7 minutes, until browned.

To assemble an open-face sandwich: take one slice of bread and spoon half of the egg salad on top. Spread evenly across and then top with some of the crispy leeks. Repeat with other slices of bread.