Prepare the Buttermilk Mixture:
In a bowl, combine the milk and vinegar. Stir well and let it sit for 5 minutes to create a buttermilk mixture.

Mix Wet Ingredients:
To the milk-vinegar mixture, add the eggs, vegetable oil, vanilla extract, and a pinch of salt. Whisk until smooth.

Combine Dry Ingredients:
In a separate bowl, mix the sugar, flour, cocoa powder, baking soda, and baking powder until fully combined.

Combine Wet and Dry Ingredients:
Gradually add the wet ingredients to the dry ingredients. Mix until smooth, ensuring no lumps remain.

Add Coffee:
Stir in the warm coffee. The batter will be slightly runny, but this is expected and helps create a moist cake.

Prepare to Bake:
Grease your baking pan (9-inch round or square) with butter or non-stick spray. Pour the cake batter into the pan, spreading it evenly.

Bake the Cake:
Preheat the oven to 175°C (350°F) and bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.

Make the Chocolate Ganache:
While the cake is baking, prepare the ganache. In a small saucepan, heat the cream over medium heat until it begins to simmer. Remove from heat and pour it over the chopped dark chocolate and butter in a bowl. Stir until the chocolate melts and the ganache becomes smooth.

Assemble the Cake:
Once the cake is baked, let it cool in the pan for 10 minutes before transferring it to a wire rack to cool completely. After the cake is cool, pour the chocolate ganache over the top, spreading it evenly.