Grease and line a 8x10 inch baking sheet and set it aside.
In a bowl, add the milk and instant coffee, mix until the coffee dissolves (it helps if you use warm milk). Now add the oil, vanilla and vinegar, whisk really well. Set aside.
In a separate bowl, sift the flour, cocoa powder, baking soda and salt. Add the sugar, stir to combine.
Now make a well in the dry ingredients and pour the liquids that we mixed earlier into it.
Mix gently, it is preferred if you just fold the ingredients with a spatula just until it is combined. Do not overmix your batter.
Pour this batter into your prepared baking tray and bake for 12-15 minutes. The baking time varies depending on the heat of your oven. You will know the cake is done when a toothpick inserted in the center of the cake comes out clean.
Let the cake cook completely on a wire rack before assembling. You can also chill the cake to make it easier to work with.
Heat the cream in a microwave or in a heavy bottom saucepan till it reaches a simmer. Remove from the heat.
Add the chopped chocolate and let it sit for 5 minutes.
Add some salt and stir until the ganache becomes shiny and smooth.
Assembling the cake
I wanted to go for the look that you see in the pictures so I cut the cake into 4 pieces. 5 inches by 4 inches each.
I started by placing one layer at the bottom and adding around 4 tbsp of ganache and spreading it evenly continuing with alternate layers of cake and ganache. In the end I spread the remaining amount of ganache on top of the cake.