As a first step, make your hazelnut butter. Add ½ cup of dry or roasted hazelnuts to a food processor and blend until a smooth nut butter forms. Depending on your blender this can take anywhere from 5-15 minutes. Store-bought nut butter will also work and in that case use ¼ cup hazelnut butter in the recipe.
Once the nut butter is ready, add your liquid aquafaba to a metal mixing bowl. Use an electric mixer to whip the liquid until stiff white peaks form.This can take anywhere from 10-15 minutes . The aquafaba is ready when it is white in color, has more than tripled in volume, and the bowl can be inverted without the aquafaba sliding out.
After the aquafaba is ready, melt your chocolate. Once melted, add in the hazelnut butter, coconut cream, and vanilla bean paste and stir until evenly combined. Let cool until slightly warm before adding to the aquafaba.
Next, gently fold the luke-warm chocolate hazelnut mixture into the mixing bowl containing the whipped aquafaba until no streaks of chocolate remain. Don’t worry if your mixture deflates at this time as that is perfectly normal.
Pour the vegan mousse into 4 small parfait jars or glasses. Cover and place in the fridge for at least 4 hours or, ideally, overnight.
Right before serving, make your vanilla coconut cream topping. Add the refrigerated coconut cream, vanilla bean paste/extract, and powdered sugar to a standing mixer or large bowl. Whip until light and fluffy.
Remove the containers of mousse from the fridge and top with the vanilla coconut cream and chopped hazelnuts. Enjoy!