Preheat your oven to 350°F (175°C). Pulse toasted hazelnuts into a fine meal, combine with melted butter and sugar. Press into a tart pan and pre-bake for 10-12 minutes.

Create the filling by whisking together Nutella, eggs, and heavy cream until smooth and glossy.

Pour the filling into the crust and bake for 20-25 minutes until the edges are set.

Allow to cool at room temperature for 30 minutes, then chill in the refrigerator for at least 2 hours.

Whip heavy cream until soft peaks form, fold in chopped hazelnuts.

Remove tart from refrigerator, top with whipped cream, and optionally sprinkle with more hazelnuts.