Step 1: Prepare Batter

In a bowl, combine the flour, salt, egg and egg yolk. Then pour milk, stirring slowly and constantly. When half the milk is added, stir in the melted butter and vanilla. Beat well until smooth. Pour remaining milk. Cover and keep at room temperature for at least 20 minutes before using it.

Step 2: Prepare Crepes

Heat a frying pan and spread little melted butter in the frying pan. Add 1/4 cup batter. Tip skillet from side to side until batter covers the bottom. Cook until the bottom is golden brown, turn and remove to a plate. Repeat with the remaining batter. Spread a thin layer of chocolate hazelnut onto Crepe and place banana slices down the center. Roll or fold crepe and place it on a serving plate. Spread hazelnut chocolate over the Crepe.