Method

Preheat the oven to 180 °C. Grease and flour a 25-cm tube pan. Line the bottom and the sides (about 2.5 cm) with baking paper.

Place the chocolate and the butter in a large ovenproof (Pyrex) mixing bowl. Bring the water to the boil, then pour over the chocolate and the butter, stirring until completely melted and smooth. Stir in the vanilla essence and the sugar, then whisk in the egg yolks, one at a time, until well blended.

Stir the bicarbonate of soda into the sour cream. In a separate bowl, combine the flour, baking powder and spice. First whisk the sour cream into the chocolate batter, then add the flour mixture, whisking until smooth and well blended.

Using an electric mixer, beat the egg whites until stiff peaks form. Fold about a third of the whipped whites into the chocolate batter until most of the white has disappeared, then fold in the rest of the whites in one or two additions. Try not to overwork the batter as you will beat out the air incorporated with the egg whites, but don’t be afraid to really fold and make sure no white lumps of any size remain or your finished cake, gorgeously dark, will have white spots in it.

Carefully pour the batter into the prepared pan and bake for 40–50 minutes, until the cake is set and a tester stuck into the cake comes out clean. (When I touched and gently pressed the surface of my cake at 40 and then 45 minutes I felt liquid or unset batter under the surface. After another couple of minutes, I touched and gently pressed the surface again and felt some resistance and knew that it was time to stick in a tester. Watch the cake carefully at the end as you neither want this cake underdone nor overdone and dry.)

Remove the cake from the oven and place onto a cooling rack. Allow the cake to cool completely before loosening it from the sides of the pan (and the inner tube) with a sharp knife and carefully lifting it out. If you have lined the pan with baking paper, you can grip the edges of the paper and lift it out of the pan. Place a rack on the top of the cake, flip it over, peel off the baking paper from the bottom of the cake, place your serving platter onto the upturned bottom of the cake and then flip upright.

Chocolate ganache

Place the chocolate in a medium-sized heatproof bowl. Bring the cream to a boil. Pour it over the chopped chocolate and allow to stand for 1 minute, then stir until the chocolate is completely melted and the ganache is perfectly smooth. Leave it standing at room temperature until it reaches the desired consistency: when drizzling over the cake, it should retain its pouring consistency yet be just thick enough so that it doesn’t all run off and form a puddle around the cake.

Christmas spice

Mix together all the ingredients to make the Christmas spice. You can also add the zest of a half or whole orange.

Variation

What I love about cakes where you use water is that all or part of the water can be replaced with other liquids to change the flavour of the cake: you can replace part of the water with strong coffee, orange juice or even the juice from jarred fruit such as cherries or blueberries. Just taste before using more than half a cup of flavoured liquid. And make sure if you choose to replace some of the water with another liquid that it goes well with whatever spice you decide to add. Or leave out the spice completely because this cake is delicious even without added spices. And a dash of Amaretto or rum never hurt anyone …