In a blender, combine flour, milk, melted butter, eggs, sugar, and salt. Blend until smooth and let the batter rest for at least 30 minutes in the refrigerator.
Heat a non-stick skillet over medium heat and lightly grease it with butter. Pour about 1/4 cup of batter into the pan, swirling to cover the bottom evenly.
Cook the crepe for about 1-2 minutes on each side until lightly golden. Remove from the pan and repeat with the remaining batter.
Allow crepes to cool. Spread a thin layer of Nutella between each crepe, stacking them as you go, finishing with a crepe on top.
Refrigerate the assembled crepe cake for at least 1 hour before slicing and serving.