Prepare the Baking Sheets: Start by aligning two baking sheets with parchment paper or silicone mats, ensuring they're flat for even baking.

Sift the Dry Ingredients: In a mixing bowl, combine almond flour and powdered sugar thoroughly. Use a fine sieve to sift the mixture at least twice.

Whip the Egg Whites: Using a clean mixing bowl, begin whipping egg whites at medium speed until frothy. Gradually add granulated sugar until stiff peaks form (~5-7 minutes).

Fold in the Dry Ingredients: Gently fold the sifted almond flour mixture into the whipped egg whites using a spatula until uniform.

Pipe the Macarons: Transfer the macaron batter into a piping bag and pipe small circles of batter onto the baking sheets.

Rest the Macarons: Allow the piped macarons to rest at room temperature for 30 to 60 minutes until a thin skin forms on their surface.

Bake: Preheat oven to 325°F (160°C). Bake the macarons for 12 to 15 minutes until foot forms and they have a slight sheen.

Make the Filling: In a saucepan, heat heavy cream until simmering. Pour hot cream over Nutella and stir until smooth.

Assemble the Macarons: Pair macarons into matching sizes, pipe a dollop of ganache on one shell, and sandwich with another shell.

Garnish: Roll the edges of the assembled macarons in chopped hazelnuts. Place on a serving platter.