01 - Whisk flour and salt in a large bowl. Create a well in center, add eggs, and gradually whisk in milk and melted butter until smooth. Rest batter for 10 minutes.
02 - Heat nonstick pan over medium heat, lightly buttered. Pour 1/4 cup batter, swirling to coat bottom thinly. Cook 1-2 minutes until edges lift and golden, flip 30 seconds. Repeat with remaining batter.
03 - Preheat oven to 350°F for final baking.
04 - Layer ham slices, spinach, cheese, and crème fraîche on each crepe. Season with black pepper. Fold into quarters or roll up.
05 - Arrange crepes in baking dish, sprinkle with remaining cheese. Bake 8-10 minutes until cheese melts and crepes are heated through.
06 - Serve immediately, garnished with fresh spinach or accompanied by side salad if desired.