Incorporating cake into your diet requires allowing yourself wiggle room for naughtiness in your schedule while planning for the inevitable lack of wiggle room in your trousers if you indulge a little too frequently without enough activity. I’ve definitely been embracing the former without enough of the latter recently and I need to tell you why! Chocolate cake! And I’m not talking about any of your mousse or gateau nonsense. I’m corresponding in rich dense sponge paired with tarty jam and a dark chocolate icing so shiny you could do your hair with it – The Sachertorte. This cake is a Viennese specialty and is celebrated every year in Austria on the 5^th of December during National Sachertorte Day, which is doubly impressive considering it was invented by a sixteen year-old apprentice called Franz Sacher for Prince Metternich in 1832. This final fact belies the sophistication of the recipe for this dark, dignified and brooding cake that is unmistakably proof of a cake God. Franz Sacher managed to build a career this classic European chocolate sugar high and his original recipe is a secret (to try it you must visit the Sacher Hotel in Vienna) so in the following I present a “runnning4cake torte”.

 As the Sachertorte sponge uses egg whites to create volume as opposed to raising agents like baking powder it means that it has a denser sponge that can appear dry (though I didn’t find this). Rather than tinkering and tweaking the recipe to compensate for an ailing dry sponge tradition dictates that the cake should be served with complementary whipped cream to moisten each spongy mouthful. As this is a classic cake I’ve adhered to this tradition except that I decided to use clotted cream because I can.

(Serves 12)

• 345g dark chocolate (chopped)
• 300g granulated sugar
• 125g icing sugar
• 125g unsalted butter
• 6 large eggs, separated
• 1 tsp of vanilla extract
• 125g plain flour
• Pinch of salt
• Apricot jam
• Clotted Cream
• 120ml of water
• 1/2 tsp of vegetable oil

Firstly I melted 180g of my dark chocolate – I used Lindt 70% cocoa chocolate, as it happened to be on offer at the supermarket.

Never missing an opportunity for some exercise I beat (by hand!) the butter in a mixing bowl until it was light and creamy before gradually adding the icing sugar and beating again until it returned to its light and creamy texture. Then I beat in the egg yolks one at a time before adding the cooled chocolate and vanilla and (yep you guessed it) beating it further.

In a separate mixing bowl I whisked (by hand!) the egg whites with a tablespoon of granulated sugar until is appeared foamy before gradually adding 100g of the granulated sugar. The mixture will transform from its foamy fluid phase to a thicker opaque state. The real art to this stage is knowing when to stop. If fatigue doesn’t stop you earlier you want to stop whisking when you can form firm peaks in the mixture – peaks that hold form except that the tips can fold back on themselves.

Then I folded the egg whites into the chocolate mixture to minimise compromising the hard whisking efforts of the previous step before folding in a sifted mixture of the plain flour and salt. I added this batter to a 9-inch high-sided baking tin and placed it into a pre-heated oven (190°C) for 35 minutes (or until a kebab skewer inserted into the middle comes out clean).

Then I allowed the cake to cool on a rack before slicing it into two even layers. Spread a generous helping of apricot jam onto the bottom layer before returning the second layer onto the top of the cake and adding a little more jam to the outside of the sponge.

Now for the difficult bit! The chocolate glaze! Ideally you want your glaze to be immaculately smooth and shiny for maximum visual impact. I added 200g of granulated sugar to 120ml of water in a saucepan. The shiny aesthetic is very sensitive to the temperature of this mixture. I don’t have a sugar thermometer so I used the ‘sugar test’ – to do this I heated the mixture on medium heat while stirring until it is was boiling.

Then I extracted a little of the sugar solution and dropped it into a bowl of cold water. If the sugar is at the correct temperature you will be able to pick up the sugar in the water and form it into a squishy ball. If the temperature is too low the sugar will form threads in the water. Once I had the soft ball regime I removed the saucepan from the heat and whisked in 115g of dark chocolate. I immediately (this is key!) poured the hot mixture over the top of the cake – I tried to be strategic with my pouring because I wanted to eliminate the need to use a knife to spread the glaze, which could have broken the beautiful uniformity of the glaze.

No sachertorte would be complete without a final chocolate writing flourish. For this step I simply melted 50g of chocolate and mixed in ~1/2 a tsp of vegetable oil. I added this to a plastic sandwich bag and snipped off the corner to make a small hole before piping directly onto the top of the cake.

I allowed the cake to set for about an hour before brewing up a fresh batch of coffee, adding a dollop of clotted cream to my plate and a generous slice of this magnificent cake.