No-bake chocolate cake
A chocolate cake that sets in the fridge holds together through cold, not cooking. The ratios that guarantee clean slices, and the three mistakes that leave it soft.
A no-bake chocolate cake does not hold together the way a baked one does. There is no coagulated egg, no gelatinised starch, no gluten: it is the fat, set solid by cold, that provides the entire structure. Everything else follows from that, including the failures.
That was the first thing I understood after pulling three refusing-to-unmould mixtures out of the fridge.
What holds the cake together
In a no-bake cake, only three elements do any work.
The chocolate, which sets below roughly 20 °C and provides most of the hold. The added fat, butter or cream, which also sets but more softly. And the dry part, usually crushed biscuits, which absorbs and gives body.
A cake that will not set always has the same fault: too much liquid relative to the chocolate. It is almost never a question of time in the fridge.
The ratios that work
Here is the ratio I use, starting from 200 g of dark chocolate at 55 or 60 %.
| Element | Amount | Its job |
|---|---|---|
| Dark chocolate | 200 g | The structure. Below this, the cake stays soft |
| Butter | 100 g | The richness. Past 120 g it will not slice |
| Dry biscuits | 200 g | Body and crunch |
| Liquid (cream, milk, coffee) | 60 to 80 ml max | The binding, and nothing more |
The critical line is the last one. Past 100 ml of liquid per 200 g of chocolate, the cake will not set, however long it spends in the fridge. It is the one mistake that cannot be corrected. The other ways of doing without an oven are more forgiving on this point.
Milk chocolate and white chocolate contain less cocoa butter structure and more sugar, so they set less. If you use them, go up to 250 g and down to 50 ml of liquid.
The method, step by step
Crush the biscuits, but not to powder. You want 3 to 5 mm pieces. Reduced to flour, they absorb everything and give a texture like modelling clay. A freezer bag and a rolling pin will do; a food processor goes too far too fast.
Melt the chocolate and butter together, gently. In a bain-marie or in the microwave in 20-second bursts. Chocolate scorches from around 50 °C and turns grainy: at that point it is lost.
Let it cool slightly before mixing with the biscuits. If the mixture is scalding it softens the biscuits, which lose all their crunch.
Press down firmly in the tin. This is the step everyone rushes. A poorly pressed cake crumbles when sliced. I press with the back of a spoon until the surface turns smooth and shiny.
Four hours in the fridge minimum, overnight is better. Two hours is never enough for a 20 cm tin.
The crisp base, if you want two textures
To get a firm base and a creamy top, without the resting constraints of a shortcrust pastry, split it into two mixtures: a base of biscuits and melted butter only, pressed down and chilled for 20 minutes, then the chocolate mixture on top.
The base holds with 60 g of butter per 200 g of biscuits. Less and it crumbles; more and it turns greasy and soft out of the fridge.
The three classic failures
It will not set. Too much liquid, almost always. Fix: melt the whole thing again with an extra 50 g of chocolate and set it a second time.
It is hard as a rock. Too much chocolate relative to butter, or too high a cocoa percentage. A 70 % sets far harder than a 55 %. Taking the cake out 20 minutes before serving is usually enough.
It crumbles when sliced. Badly pressed, or cut straight from the fridge with a dry knife. Running the blade under hot water and wiping it between slices changes everything.
How long does it keep
Four to five days in the fridge, covered, with no loss of quality. It freezes very well for a month, sliced and separated with baking paper, which lets you take out one portion at a time.
It does not, however, tolerate waiting at room temperature: beyond two hours in a 22 °C room it starts to slump. This is a dessert you bring out at the last moment.
Frequently asked questions
Can it be made without butter? Yes, replacing it with the same weight of double cream, but the set will be softer and you will need to drop the liquid to 40 ml. The principle is the same as with gluten-free cookies: removing an ingredient means first removing whatever it was holding up.
What tin should I use? A springform tin, or a tin lined with cling film with plenty of overhang. A fixed tin with no lining is impossible to unmould cleanly.
Can the biscuits be swapped? For speculoos, shortbread or wafers, yes. For soft biscuits like madeleines, no: they do not absorb and the cake stays pasty.
Does it need extra sugar? Almost never. The biscuits and chocolate already bring plenty. If you use 70 % chocolate and barely sweetened biscuits, 20 g of icing sugar in the mixture is enough.