Whisk together flour and salt in a medium bowl.
Make a well in the middle and whisk in half the eggs, followed by half the milk.
Add remaining eggs and milk, then stir in the melted butter.
Cover and leave to stand for at least an hour.
Heat ham and gruyere in a skillet over low heat until warm and melty.
Warm a frying pan over a medium-high heat and grease with butter.
Give your crepe batter a good whisk to recombine before cooking.
Pour in ladleful of batter tilting the pan to cover the base.
Cook until the edges turn brown, then loosen with spatula and flip (~30-40 seconds each side).
Add your filling in the middle of the crepe, and fold edges over onto the filling.
Serve immediately, or store in a warm oven until you’re ready to enjoy!
