Cream the softened butter and sugar together in a mixer on high speed until light and fluffy and doubled in volume.
Whisk the eggs together.
Add a small amount of the egg mixture to the butter and mix well until combined.
Slowly add the remaining eggs to the mixture while mixing.
Add a teaspoon of vanilla extract or to taste, the clarified butter and mix well.
Sift the flour, salt and baking powder together.
Add the flour mixture and mix on medium speed until just combined.
Mix the cocoa powder with hot water until you have a thick, double-cream-like consistency.
Add the chocolate to the mixture and mix well until smooth.
Grease and flour a tart pan or line it with parchment paper and pour in the batter.
Bake at 160°C (325°F) for 40 minutes.Check for doneness by inserting a knife. If it comes out clean, the cake is ready. Let cool before cutting.
Ganache (Cake topping.):Bring the cream to a boil and pour it over the chocolate. Add ¼ teaspoon of vanilla extract and the sugar.
Mix well until the chocolate melts.
Add 1 teaspoon of butter and mix until dissolved.
When the ganache is still melted but not too hot, pour it over the fudge cake while it's still in the cake tin.
Let it cool until it's firmer and then refrigerate until completely chilled.
Enjoy!
