Combine all ingredients in a blender and blend on low speed until combined, scraping down sides as necessary.
Heat a non-stick skillet to medium-high heat. Hold pan with one hand while you pour the batter with the other hand. Twirl the pan in a circular motion pouring just enough batter to coat the bottom of the pan. Place on cooking surface and cook until edges are set and you can easily run a rubber spatula around the edge of the pan, 30 seconds. Flip crepe and cook an additional 15-20 seconds. Remove crepe from pan and either keep warm in the oven or cool to room temperature. *You can choose the size of pan by the circumference of cake you want. Keep in mind smaller crepes will produce more, and therefore a taller cake, but fewer slices. In my photos I used a 10" skillet and that is as large as I would go.
Cool crepes completely before using to assemble cake.
Mousse
Place gelatin in a tiny bowl and add 1 teaspoon cold water. Let sit for 5 minutes and then add 1 tablespoon boiling water and stir until smooth. Place cream, powdered sugar, vanilla, and hazelnut in a stand mixer with the whisk attachment on. Beat for about 1 minute and then slowly drizzle in the gelatin in a tiny stream.
Continue beating until a little firmer than standard whipped cream (but don't turn it into butter! I do stiff peaks). Remove and set in a separate bowl. Place cream cheese in mixer and beat until soft and creamy, add Nutella a little at a time and beat until incorporated. Remove bowl from mixer and gently fold the whipped cream into the cream cheese mixture in 3 additions.
Cake Assembly
Place a completely cooled crepe on a plate or cake stand and spread on about ¼ cup Nutella mixture. Add another crepe and continue until crepes or mousse is gone! If desired, double the ganache listed and use half for the top of the cake and use the rest to spread after every few crepes on the inside.
Ganache
Heat cream in microwave safe bowl until steaming. Add chocolate chips and let sit for 5 minutes and then whisk until smooth. Spread on top of cake and gently spill over edges. Garnish with berries and chocolates. Store cake in fridge if not serving right away and set out at room temp for a few minutes before serving.
Notes
Chocolate Dipped Strawberries: I just eyeball my dipping chocolate, but use about 1 teaspoon coconut oil (or canola oil) per 1 cup of chocolate chips. Place both in a microwave safe bowl and heat in 30 second intervals, stirring after each one, until melted and smooth. Hold berries by stems and gently dip in chocolate and then place on parchment paper or a silicone liner. Let sit until chocolate is firm.
The size of your cake will depend on the size of your crepes. I used an 8-9" skillet and got about 20 crepes.
Nutritional information note: this cake was calculated without the use of any garnishes, such as Ferrero Rocher.
Store leftover crepe cake tightly covered in the refrigerator and eat within 2-3 days for best results.
For ease in assembly, make your crepes ahead of time. Place a piece of parchment between them for easy separation.