In a medium bowl, whisk together 3 medium eggs, 1 cup whole milk, 1 cup all-purpose flour, 1/2 teaspoon kosher salt, and 2 tablespoons minced chives until smooth. Cover and let it rest for at least 1 hour.

Heat a non-stick skillet over medium heat, add 1 teaspoon unsalted butter. Pour about 1/4 cup crepe batter and swirl to spread. Cook 2 minutes until edges lift, then flip and cook 1 more minute.

Preheat oven to 400°F (200°C) and line a baking sheet with parchment paper.

On each crepe, spread 1 teaspoon of Dijon mustard, add 1/4 cup shredded Parmesan cheese, and crack 1 medium egg in the center. Fold the edges over to create a square.

Place folded crepes on the baking sheet and bake for about 10 minutes, until egg whites are set but yolks remain runny.

Remove from the oven, optionally sprinkle fresh herbs on top, and serve warm.