In a mixing bowl, whisk together flour, eggs, milk, melted butter, sugar, vanilla extract, and salt until smooth. Let the batter rest for about 30 minutes at room temperature.
Heat a non-stick skillet over medium heat. Lightly grease with butter. Pour about 1/4 cup of batter into the skillet, swirling to coat the bottom evenly. Cook for about 1-2 minutes until the edges lift and the bottom is lightly golden. Flip and cook for another minute. Repeat with remaining batter, stacking cooked crepes on a plate.
In a mixing bowl, beat the heavy cream until soft peaks form. Gently fold in the chocolate hazelnut spread, powdered sugar, and vanilla extract until well combined.
Place one crepe on a serving plate. Spread a generous layer of the chocolate hazelnut cream on top. Sprinkle with a layer of crushed hazelnuts. Repeat this process, layering crepes and cream until you use all crepes, finishing with a layer of cream on top.
Once fully assembled, cover the cake with plastic wrap and refrigerate for at least 2 hours or overnight for better flavor melding.
Before serving, sprinkle the top with additional crushed hazelnuts for garnish. Slice into wedges and serve chilled or at room temperature.