01 - Whisk together flour and salt in a large bowl. Create a well in center, add eggs, then gradually whisk in milk and melted butter until smooth. Rest batter for 10 minutes.
02 - Heat nonstick crepe pan over medium heat, lightly buttered. Pour 1/4 cup batter, swirling to create thin layer. Cook 1-2 minutes until edges lift and golden, flip 30 seconds. Repeat with remaining batter.
03 - Preheat oven to 350°F.
04 - Layer ham slices, spinach, cheese, and crème fraîche on each crepe. Season with black pepper.
05 - Fold crepes into quarters or rolls. Arrange in baking dish, top with remaining cheese.
06 - Bake 8-10 minutes until cheese melts and crepes are heated through. Serve hot.