Prepare the Nutella Cake: Preheat the oven to 350°F/175°C. Place the hazelnuts on a rimmed baking tray and spread out evenly. Roast in the oven for 10-15 minutes or until lightly browned and very fragrant. Allow the hazelnuts to lightly cool.

While the hazelnuts are roasting, line a 9×5-inch loaf pan (23 x 13 x 8 cm pan) with parchment paper, with the ends hanging over sides of the pan. If you don’t have a loaf pan, you can use an 8×8-inch square pan (20 x 20 x 5 cm).

Place the hazelnuts on top of a clean kitchen towel and wrap into a bowl. Rub vigorously to remove the hazelnut skins. It’s not necessary to remove all the skins.

Place the hazelnuts in a food processor or high-powered blender until finely ground (but don’t blend too much, you don’t want it to turn into nut butter).

Add the almond flour, dates, cacao powder, salt, and vanilla and process until you have a sticky dough that you can press together with your fingers Stir in cacao nibs with a silicone spatula.

Transfer the Nutella cake dough to the lined pan. Using your hands and/or a silicone spatula, press the dough into the bottom and sides of the pan until it is flat and firm.

Freeze the cake for 30 minutes to set, or refrigerate for 1-2 hours.

When ready to serve the cake, make the Chocolate Avocado Frosting. Place avocados, cacao powder, maple syrup, and salt in a food processor and blend until creamy and smooth. You should get 3/4 -1 cup of frosting.

To serve the cake, spread the frosting on top of the cake and sprinkle a generous amount of flaky sea salt on top. Store leftovers in the freezer for 2-3 days. If you want the leftovers to last longer, just frost the portion of the cake you plan to eat in the next few days. The unfrosted cake will stay good in your freezer for a month or two.