In a small saucepan, heat 1/2 cup of heavy whipping cream over medium until just simmering. Remove from heat and stir in 4 ounces of 63% dark chocolate and 1 tablespoon of unsalted butter. Mix until smooth, then add in 1 tablespoon of light corn syrup and a pinch of fine salt. Allow the ganache to sit at room temperature, thickening as it cools.

Separate 3 aged egg whites and let them sit at room temperature for at least 24 hours prior to beating. In a stand mixer, whisk egg whites on medium speed until foamy. Gradually add in 3 tablespoons of granulated sugar, continuing to whisk until stiff peaks form, which should take about 5-7 minutes.

In a separate bowl, sift together 1 cup of superfine almond flour, 1.5 cups of powdered sugar, and 1/3 cup of cocoa powder. Gently fold this dry mixture into the meringue using a spatula until just combined.

Transfer the macaron batter into a piping bag fitted with a round tip. On a baking sheet lined with parchment paper, pipe bear-shaped outlines, each about 1.5 inches wide. Allow the piped batter to rest for 30 minutes at room temperature until a skin forms.

Preheat your oven to 300°F (150°C). Once the macarons have rested, bake in the oven for 19-21 minutes. Allow them to cool completely on the baking sheet before removing them.

In a bowl, combine 2 cups of powdered sugar with 1 tablespoon of meringue powder and 1/4 cup of water. Mix until smooth, adjusting with more water if necessary. Divide to color with black gel food coloring.

Use a piping bag fitted with a fine tip to pipe little details on the cooled macaron shells to create bear faces. Allow the icing to harden at room temperature for at least 30 minutes.

Take your prepared ganache and pipe a dollop onto the center of half of the macaron shells. If using, add a small spoonful of Nutella on top of the ganache. Place the remaining shells on top to sandwich.

To enhance flavor, refrigerate the assembled macarons for at least 12 hours. Before serving, let them sit at room temperature for 30 minutes.