Preheat your oven to 350 ?F (175 ?C).

In a large bowl, mix together sugar, flour, cocoa powder, baking powder, cinnamon, and salt.

Add oil, milk, vanilla, and egg to the dry ingredients; whisk until smooth.

Pour the batter into a greased, floured, and parchment-lined 8-inch round cake pan. Bake for 37-40 minutes or until a toothpick inserted in the middle comes out clean or with a few crumbs.

Chop and fluff up the kataifi pastry with your hands.

In a pot over medium heat, melt butter and add kataifi pastry, stirring frequently to keep it fluffy. Toast until deep golden brown, then let cool.

Melt white chocolate (and vegetable oil if using), mix in pistachio butter and salt, and let cool until slightly thickened.

Combine the toasted kataifi pastry with the pistachio cream.

Whip the heavy cream until soft peaks form; add honey and whip until combined. Fold in melted dark chocolate and keep refrigerated.

The next day, trim the dome of the chocolate cake and slice it into two layers.

Place the first layer on a cake platter, pipe a border of dark chocolate ganache, and fill with the pistachio and kataifi mixture.

Place the second layer on top and frost the cake with the remaining whipped chocolate ganache.

Smooth the surface of the cake with a warm offset spatula and sprinkle with chopped pistachios.