Hot Chocolate Sponge

Hot chocolate sponge cake, topped with Bar One ganache decorated with marzipan modelled vegetables 

Within the world of cakes, this hot chocolate sponge is most closely allied to a Génoise cake, or pan di Spagna, an Italian sponge cake, both of which are leavened with beaten whole eggs. What differentiates this one from them, and is why it was dubbed an “Infallible Chocolate Cake” in Lesley Faull’s book, is that it also incorporates a chemical leavening agent in the form of the baking powder. However, the cake will not be infallible unless you adhere to the basic rules of baking this kind of cake, which are not noted in the old-style recipe books, they just used a kind of shorthand – beat eggs and sugar together – figuring you knew the rest. However, if you do know what to do, you will end up with a light, dry, springy sponge, which like all sponges, uses hardly any butter at all, all the better for weight-watching.

Hot Chocolate Sponge Recipe

4 Tablespoons hot water 

1 Tablespoon butter (13 grams)

4 teaspoons cocoa 

1 Tablespoon golden syrup (20 grams) 

3 whole eggs

190 grams castor sugar (1 cup)

125 grams cake flour (1 cup)

2 teaspoons baking powder 

Pinch of salt 

1 teaspoon vanilla essence

Preheat the oven to 180°C, 350°F, gas mark 4. 

One of the delightful things about this cake is that it is virtually butter-free, but this means that the leavening is provided by the air that is beaten into the eggs. Hence, before you begin beating the eggs, make sure the oven is pre-heated, the rest of the sets of ingredients – dry and wet – are mixed and ready, and the bottom of the cake tins lined as you need to work quickly and get it into the oven before the bubbles start popping, thanks to gravity, and your cake bakes flat and heavy instead of light and airy. For this reason as well, do not even think of substituting ordinary sugar for castor sugar. 

Place water, butter, cocoa and syrup in small pan and dissolve over low heat, stirring to ensure the cocoa is distributed evenly throughout, remove from heat immediately. If you do forget, you can bring down the temperature quickly by placing the pan in a sink filled with water and ice. Mix the flour (which must be well-sifted), the baking powder and salt together, stirring to ensure even distribution, lest volcanic eruptions occur in your cake due to an excess of rising agent in one place. 

In essence, making this cake is a bit like making a meringue with whole eggs and then folding in the rest of the mixture, so I’ve therefore adapted the recipe accordingly. The French way is to warm the eggs – to ensure volume. Of course, you only ever must use room temperature eggs; I keep mine outside the fridge, always (but I buy fresh-laid eggs and use them within a week). Cold eggs can easily be brought to room temperature by placing them in a luke-warm water bath. The steel mixing bowl of my Kenwood works perfectly in terms of raising or lowering temperatures - just place the eggs in it, and the container in a sink filled with a few centimetres of warm water.

Beat eggs with the egg-whisker attachment of your cake beater until light and frothy and about tripled in size. Next, add the castor sugar, spoon by spoon, to the mixture while it is still beating, again, taking the method from that of making meringues, working quickly all the time since over-beating eggs is also a problem. In most cakes, you beat air into the butter, or butter and eggs, in this case, it is into the eggs only. Bearing in mind that the rising agents (baking powder in this case) make the cake rise not by creating air bubbles but by expanding the air bubbles you have already beaten into the mixture, you therefore must take time and care over this part - the final mixture should look creamy, even white. Gently fold in half the flour mixture into the egg mixture – a ball whisk will do, or a spatula – my grandmother taught me to sprinkle the flour on top then shake the spatula, but whisks are easier on your wrists; either way, be sure to add the flour incrementally and not all in one large blob. Next, add the cocoa mixture – make sure it is not too hot else it will start to cook the eggs, then the rest of the flour - this way, you ensure full incorporation of the cocoa mixture into the cake. Lastly add the vanilla.

Bake in moderate oven – 180C for 18 to 20 minutes in two sandwich tins. The cake will rise significantly and then drop a little again. Sponges are highly sensitive to oven temperature and times, if you take it out too soon – one flat cake will result. The final cake should be soft and springy to the touch. Cool on wire rack.

The original recipe advocated two small round tins, while you can double the mixture and put in one large pan (hence, effectively, quadrupling the depth), and while it will cook through, it will have a tendency towards cracking across the middle, with a crispier outside – not necessarily the result desired. In my son’s case, however, he wanted this cake made large, so we did it – effectively having also to quadruple the time to about 50 minutes – but I would advocate sticking to the original recipe, personally. He insisted on decorating it with the usual butter icing, however, since the cake is so light, I have also undertaken a variant of a Hot Chocolate Ganache with it.

Nothing quite like eating a cake straight from the oven for breakfast!