1. In another bowl, beat the sugar, eggs, buttermilk, vegetable oil, and vanilla until smooth.
2. Gradually add the dry ingredients to the wet mixture, mixing until just combined.
3. Stir in the boiling water (the batter will be thin).
4. Pour the batter evenly into the prepared pans.
5. Bake for 30-35 minutes or until a toothpick comes out clean.
6. Allow cakes to cool completely on wire racks.

2. Make the Hazelnut Cream Filling:

1. Whip the heavy cream until soft peaks form.
2. Fold in the Nutella until smooth.
3. Gently mix in the chopped roasted hazelnuts.

3. Prepare the Chocolate Ganache:

1. Heat the heavy cream until just simmering.
2. Pour over the chopped chocolate and let sit for 2 minutes.
3. Stir until smooth, then add the butter and mix until glossy.

4. Assemble the Cake:

1. Place one cake layer on a serving plate.
2. Spread a generous layer of hazelnut cream filling.
3. Place the second cake layer on top.
4. Pour the ganache over the cake, letting it drip down the sides.
5. Decorate with crushed and whole Ferrero Rocher chocolates and chopped hazelnuts.

Recipe Variations

• Gluten-Free Option: Substitute all-purpose flour with a gluten-free blend.
• Vegan Version: Use plant-based milk, egg replacers, and dairy-free chocolate.
• Extra Crunch: Add layers of crushed wafer cookies between the cake and filling.