1. Make a batter by mixing the flour with the milk, and adding the eggs one by one.
2. Let it rest for 30 minutes, then add the melted butter.
3. Using a crêpe pan or frying pan make about 25 to 30 very thin crêpes and set aside.
4. Make the filling by vigorously mixing the butter with the sugar, add the Grappa and keep mixing until quite airy.
5. Stack all the crêpes one on top of another on a serving plate, spreading each one with some of the filling.
6. Gently warm a few tablespoons of apricot jam and use it to glaze the top and sides of the gateau.