Preheat the Oven:
Preheat your oven to 350°F (175°C). Grease a 9-inch square or round baking pan and set aside.

Make the Cake Layer:
In a large mixing bowl, whisk together the flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt.
Add the egg, vanilla extract, milk, and vegetable oil to the dry ingredients. Whisk until smooth.
Gradually add the hot coffee, whisking until fully combined and the batter is smooth.
Pour the batter into the prepared baking pan and bake for 25 minutes, or until a toothpick inserted into the center comes out clean. Let the cake cool for 10-15 minutes.

Prepare the Pistachio Filling:
In a large heavy-duty pan, heat the butter over medium heat. Add the chopped kataifi and cook, stirring occasionally, until golden brown and crispy, about 5-7 minutes.
Transfer the toasted kataifi to a mixing bowl. Add the pistachio cream and gently mix to combine.

Make the Chocolate Layer:
Chop the milk or semi-sweet chocolate bar into small chunks.
In a microwave-safe bowl, combine the chocolate and heavy cream (or table cream). Microwave for 45 seconds, or until the cream is warmed through.
Let the mixture sit for 3-5 minutes to soften, then whisk until completely melted and smooth.

Assemble the Cake:
Once the cake has cooled slightly, spread the pistachio filling evenly over the cake using an offset spatula.
Pour the melted chocolate mixture over the pistachio layer and spread it out evenly.

Garnish and Serve:
Garnish with additional pistachio sauce, toasted kataifi, and crushed pistachios for extra texture and flavor.
Serve immediately while warm or refrigerate to allow the layers to set.