Ingredients for the cake:
190 grams (6,7 oz) butter
150 grams (5,3 oz) chocolate
20 grams (0,70 oz) cocoa powder
1 teaspoon instant coffee granules
300 grams (10,5 oz) sugar
200 ml. (7 fl oz) milk
1 teaspoon vanilla extract
2 tablespoons baileys
200 grams (7 oz) flour
1 teaspoon baking powder
2 large eggs, lightly beaten

Chocolate buttercream:
80 grams (3 oz) dark chocolate (60%), melted and cooled to room temperature
2 tablespoons baileys
125 grams (4,5 oz) butter, at room temperature
85 grams (3 oz) powdered sugar

To make the cake:
Preheat your oven to 170C (340F). Grease an 8-inch springform and line with parchment paper.
In a large saucepan add butter, chocolate, cocoa powder, coffee, sugar, milk, baileys and vanilla extract. Cook over medium temperature until chocolate, butter and sugar melt and you have a nice smooth mixture. Set aside to cool off a bit.
In the meantime combine flour and baking powder in another bowl and stir to distribute the baking powder evenly.
Add flour to the chocolate mixture and stir gently with a rubber spatula to combine. Add eggs, one by one, stirring after each egg.
Pour mixture into prepared springform and bake for about 60 minutes. If you see that top of the cake is cracking soon after you put in the oven, just lower the temperature to 160C (320F) and continue baking.
Check if cake is ready by inserting a toothpick in the center. It should come out clean but without crumbs. This cake should be moist on the inside with a nice crust on the outside.
Let cake cool to room temperature.
In the meantime prepare the chocolate buttercream:
Melt chocolate and let cool to room temperature as you stir it occasionally.
In the meantime beat butter and sugar in a large bowl until light and fluffy. Add a pinch of salt, cooled chocolate and baileys, and beat for a minute or so to combine.

Assembling the cake:
Even the top of the cake layer by cutting out the dome. Place the cake on a large platter and spread the buttercream on top. Cover the sides if you like.