This cake is ideal because if you beat it a lot it comes out fluffy, and if you beat it less it comes out fudgy, and that’s just fine either way. You can also do it with chestnut flour and golden crisco to make it both dairy and gluten free, and it’s still great.
You need an oven, a deep loose bottomed tin, greaseproof paper, a mixing bowl, a wooden spoon, a saucepan for melting butter and a way of measuring ingredients by weight.
You also need three eggs at room temperature. If you feel you absolutely must refrigerate your eggs or you will die, you’re wrong, but anyway get them out about three hours before you need to start making this cake. Really. I’m serious. All sponge cakes will be better with eggs at STP, but this one really needs it. It’s a chemical emulsification thing that won’t work with cold eggs.
Pre-heat oven to 180C, Gas 5.
Line the loose-bottomed tin with the greaseproof paper/baking parchment/waxed paper. It doesn’t have to be perfect.
Sift 4 ounces of SR (patisserie) flour, 2.5 ounces of cocoa (measures as flour in a measuring cylinder) and ten ounces of sugar into a mixing bowl. Melt 6 ounces of butter or margarine. Beat your three eggs. (Don’t forget, they have to be at room temperature.)
Pour the melted butter and the beaten eggs into the dry ingredients. Gasp in horror at what a terrible mistake this must have been, because for the first thirty seconds this looks appalling. Take the wooden spoon and beat the mixture resolutely for a measured five minutes. At some point in there, usually in the fifth minute and hopefully before your arm drops off, the stuff will change colour and become lighter. This is an indication that you’ve got enough air in it. That’s what you want, at that point you can pour it into the tin. The beating process is actually a case of adding oxygen, a chemical process, not mixing — after the first few seconds anyway. Try to fold it and get as much air in as possible. Do not use an electric whisk or a mixer. It’s impossible to tell how much air you’ve incorporated and you’ll get too much, because you can’t stop as soon as it lightens. You get a cake that’s half air and has the texture of styrofoam, and that’s OK, but it’s not what you want, and really it is worth the effort. (Also, it’s good exercise. And you’re going to be eating chocolate cake, and if you had that exercise, well, you’ll deserve it, won’t you?)
Bake in the centre of the oven for 50 minutes. Test with the clean knife method — if you poke it with a knife, it should come out clean. It’ll also have risen a lot, but you can’t rely on the colour or on bounce-back with this one.
Apart from the sheer slog of beating the air in, this couldn’t be easier. People who can’t cook can make this cake, I made it myself before I could cook.