01 - Whisk flour and salt in a large bowl. Create a well in the center, crack in the eggs, and gradually incorporate milk and melted butter. Whisk until completely smooth with no lumps. Allow the batter to rest for 10 minutes.
02 - Warm a nonstick crepe pan or skillet over medium heat. Lightly coat the surface with melted butter using a pastry brush.
03 - Pour approximately 1/4 cup of batter into the heated pan, immediately swirling and tilting to create a thin, even layer covering the bottom. Cook for 1-2 minutes until the edges begin to lift and the bottom appears lightly golden. Flip carefully and cook for an additional 30 seconds. Transfer to a plate and continue with the remaining batter.
04 - Preheat your oven to 350°F.
05 - Layer a few slices of ham, a generous handful of spinach, and a sprinkling of grated cheese onto each crepe. Add a spoonful of crème fraîche and season with freshly ground black pepper to taste.
06 - Fold each crepe into quarters or roll them up neatly. Place the filled crepes in a baking dish in a single layer. Distribute any remaining cheese evenly over the top.
07 - Bake for 8-10 minutes, or until the cheese has completely melted and the crepes are heated throughout.
08 - Serve immediately while hot, optionally garnished with additional fresh spinach leaves or accompanied by a simple side salad.