01 -
In a large mixing bowl, whisk together flour and salt. Make a well in the center, add eggs, and gradually incorporate flour into eggs. Slowly pour in milk while whisking continuously until batter is smooth. Stir in melted butter. Cover and rest at room temperature for 30 minutes.
02 -
Set a nonstick skillet over medium heat for 2 to 3 minutes. Lightly brush the pan with melted butter to evenly coat the surface.
03 -
Pour approximately 1/4 cup (60 ml) batter into the center of the hot pan. Quickly swirl to spread batter into a thin, even layer. Cook 1 to 2 minutes until edges lift and underside is lightly golden. Flip and cook 30 seconds more. Transfer to plate and keep warm. Repeat with remaining batter, brushing pan with butter as needed.
04 -
Lay one crêpe flat. Spread Dijon mustard down the center, if using. Place a slice of ham followed by a sprinkle of Gruyère cheese. Fold crêpe in half, then in half again to form a triangle enrobing the filling.
05 -
Return filled crêpes to the skillet over medium heat. Press gently and cook 1 to 2 minutes per side until cheese is fully melted and edges are crisp. Serve immediately, garnished with parsley and freshly ground black pepper if desired.