01 - Whisk flour and salt in a large bowl. Create a well in center, add eggs, then gradually incorporate milk and melted butter until smooth. Rest batter for 10 minutes.
02 - Heat a 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 bottom is golden. Flip and cook 30 seconds. Repeat with remaining batter.
03 - Preheat oven to 350°F for final baking step.
04 - Layer ham slices, spinach, cheese, and crème fraîche on each crepe. Season with black pepper to taste.
05 - Fold crepes into quarters or roll tightly. Place in baking dish and sprinkle remaining cheese over top.
06 - Bake 8-10 minutes until cheese melts and crepes are heated through. Serve hot, optionally garnished with fresh spinach or side salad.