Ingredient

Chocolate cake

Chocolate cake behaves differently from a plain sponge because cocoa is a dry, starchy, fat-poor powder that absorbs a great deal of liquid. Most of what makes a chocolate cake recipe good is how it compensates for that.

Cocoa, chocolate, and blooming

Cocoa powder gives depth and colour; melted chocolate gives richness and a softer crumb, because of its cocoa butter. The best chocolate cakes use cocoa for flavour and get their moisture from oil or buttermilk rather than from the chocolate.

Pouring boiling water or hot coffee over cocoa — blooming it — dissolves the flavour compounds properly and disperses the starch. It is the single step that most improves an ordinary recipe, and it is why so many good chocolate cake recipes contain an odd-looking mug of hot liquid.

Coffee is there for the same reason salt is: it does not taste of coffee in the finished cake, it makes the chocolate taste more of chocolate.

Why oil-based recipes stay moist

Butter

Solid at room temperature, so the crumb firms as the cake cools and reads as drier the next day. Better flavour.

Oil

Liquid at room temperature, so the cake stays soft straight from the fridge. This is why most bakery chocolate cake is oil-based.

Buttermilk or yoghurt

Acid tenderises the crumb and reacts with bicarbonate of soda for lift. Also deepens the colour.

Bicarbonate of soda

Raises the pH, which darkens cocoa considerably and gives the near-black colour of a devil’s food cake.

Hot liquid

Blooms the cocoa and thins the batter, giving a finer, more even crumb.

A reliable method

1. Whisk all the dry ingredients together thoroughly — flour, cocoa, sugar, raising agents, salt. Cocoa clumps, so this matters.
2. Whisk the wet ingredients separately — eggs, oil, buttermilk, vanilla.
3. Combine the two, then pour in the hot coffee or water last and whisk until smooth. The batter will be alarmingly thin. That is correct.
4. Divide between lined tins and bake at a moderate heat. Thin batters need slightly longer than they look like they will.
5. Test with a skewer for moist crumbs, not for a clean skewer.
6. Cool in the tin for ten minutes, then turn out. A very moist cake tears if handled hot.

Icings and fillings

• Ganache — cream poured over chopped chocolate, stirred smooth. Sets firm and glossy; the most chocolate-forward option.
• American buttercream — butter and icing sugar with cocoa. Very sweet, very stable, easy to pipe.
• Swiss meringue buttercream — silkier and far less sweet, but more work and it splits if the butter is too cold.
• Soured cream frosting — melted chocolate beaten into soured cream. Tangy and quick and cuts the sweetness.
• Nothing — a good chocolate cake with a dusting of cocoa is not a compromise.

Common questions