Start by placing the eggs in a pot and covering them with water, ensuring the water is about an inch above the eggs. Bring to a boil, cover, and let sit for 12 minutes. Peel and chop the eggs coarsely.

In a medium mixing bowl, combine the chopped eggs with mayonnaise, Dijon mustard, and sea salt. Mix gently until well incorporated and creamy but not mushy.

Lay the white bread flat on a cutting board. Using a round cookie cutter, cut out 12 circles from the bread slices, discarding the crusts.

Assemble the sandwiches by placing one bread circle on a platter, spooning egg salad onto it, topping with another circle, and pressing gently. Repeat until all sandwiches are assembled.

Finely chop parsley and sprinkle over sandwiches. Serve at room temperature.