The all-in-one chocolate cake is the recipe that makes chocolate cake accessible to absolutely everyone. No separate creaming, no adding eggs gradually, no risk of curdling — everything goes into one bowl, gets beaten together for two to three minutes, and produces a perfectly risen, deeply chocolatey sponge that is indistinguishable in quality from the traditional method.

Mary Berry has championed the all-in-one method throughout her baking career for exactly this reason — it removes the barriers to making a good cake and produces a result that genuinely does not require any technical skill beyond owning an electric hand whisk.

This recipe differs from the chocolate sponge cake recipe elsewhere on this site in one important way — it is written specifically for the all-in-one method, for people who have searched specifically for this approach and want to be completely certain they are making the simplest possible version of a great chocolate cake. The result is the same. The process is even more straightforward.

What Is the All-in-One Method?

The all-in-one method is exactly what it sounds like — everything goes into the mixing bowl at the same time and is beaten together. No separate creaming of butter and sugar. No alternating additions. One bowl, everything in at once, beat until smooth.

Mary Berry’s version adds two important details that make the method work reliably.

Bloomed cocoa. The cocoa powder is mixed with boiling water to a paste before it goes into the bowl. This releases the full aromatic compounds in the cocoa and gives a depth of chocolate flavour that the all-in-one method would otherwise slightly compromise compared to the traditional creaming method.

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Extra baking powder. The additional baking powder compensates for not aerating the butter and sugar separately during creaming. The baking powder does the leavening work instead.

Ingredients for Mary Berry All-in-One Chocolate Cake

For the Sponge

225g unsalted butter, softened to room temperature
225g caster sugar
4 large eggs, at room temperature
175g self-raising flour, sifted
50g good quality cocoa powder, sifted
2½ tsp baking powder
4 tbsp boiling water
2 tbsp whole milk
1 tsp vanilla extract

For the Chocolate Buttercream

175g unsalted butter, softened
300g icing sugar, sifted
50g good quality cocoa powder, sifted
3–4 tbsp whole milk
1 tsp vanilla extract

To Finish

Chocolate shavings or sprinkles
A dusting of icing sugar or cocoa

How to Make Mary Berry All-in-One Chocolate Cake — Step by Step

Step 1 — Bloom the Cocoa

Mix the cocoa powder with the four tablespoons of boiling water in a small bowl until a smooth paste forms. Leave to cool for five minutes. Do not skip this step — it is what gives this cake its deep chocolate flavour.

Step 2 — Preheat and Prepare

Preheat your oven to 180°C / 160°C fan / Gas 4. Grease two 20cm round sandwich tins and line the bases with baking parchment.

Step 3 — The All-in-One Mix

Place the softened butter, caster sugar, eggs, sifted flour, baking powder, milk, and vanilla extract into a large mixing bowl. Add the cooled cocoa paste.

Beat with an electric hand whisk on medium speed for two to three minutes until the batter is smooth, uniform, and slightly lighter in colour. Scrape down the sides halfway through. The batter should drop off the whisk in thick, smooth ribbons.

Step 4 — Bake

Divide the batter equally between the two prepared tins — weigh them for perfectly even layers. Smooth the tops. Bake on the middle shelf for 22 to 26 minutes until risen, set across the surface, and a skewer inserted into the centre comes out clean.

Cool in the tins for five minutes. Turn out onto a wire rack and cool completely — at least 45 minutes.

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Step 5 — Make the Chocolate Buttercream

Beat the softened butter alone for three to four minutes until very pale and fluffy. Add the sifted icing sugar and cocoa in two batches, beating well after each. Add the vanilla and enough milk to bring the buttercream to a smooth, spreadable consistency. Beat for a further two minutes.

Step 6 — Fill and Finish

Place one sponge on your serving plate. Spread half the buttercream generously over the top. Place the second sponge on top. Spread or pipe the remaining buttercream. Add chocolate shavings or a dusting of cocoa.

My Top Tips Mary Berry All-in-One Chocolate Cake

Bloom the cocoa — even with the all-in-one method. The all-in-one method is already simpler than traditional creaming. The bloomed cocoa takes two minutes and dramatically improves the depth of chocolate flavour in the finished cake. Do not sacrifice it for the sake of convenience.

Butter must be genuinely soft. The all-in-one method requires butter that gives completely when pressed with a finger — not slightly firm, not slightly cold. Take it out of the fridge at least an hour before you start.

Beat for the full two to three minutes. Under-beating gives a slightly lumpy, uneven batter and a less well-risen sponge. Set a timer and beat for the full duration.

Weigh the batter between tins. Thirty seconds on the scales. Perfectly even layers every time. Worth it.

Serving Suggestions

As an everyday chocolate cake — this is the version I make on a weeknight when I want something chocolatey and do not want to spend all evening on it. As a birthday cake for someone who prefers a lighter, less elaborate chocolate cake. As a teatime treat that keeps well for several days.

How to Store Mary Berry All-in-One Chocolate Cake

At room temperature: Store in an airtight container for up to 4 days.

In the freezer: Freeze unfilled sponge layers wrapped in cling film for up to 3 months.

Frequently Asked Questions

What is the difference between this and the chocolate sponge cake recipe on this site?

Both use the same all-in-one method and produce the same result. This post is written specifically for people searching for the all-in-one chocolate cake by name — it makes the method and its specific requirements completely explicit. The chocolate sponge cake post covers the same recipe with slightly different context and framing.

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Can I use this batter for cupcakes?

Yes — divide between 12 muffin cases and bake at the same temperature for 18 to 20 minutes.

Can I make this as a traybake?

Yes — pour all the batter into a greased and lined 30x23cm traybake tin. Bake for 30 to 35 minutes. Top with the full quantity of buttercream and cut into squares.

Can I use oil instead of butter?

Yes — replace the butter with 175ml of a neutral oil such as sunflower or vegetable oil. The cake will be slightly more moist and will keep slightly longer, but it will not have quite the same richness of flavour.

Why is my all-in-one cake dense?

Usually because the butter was too cold, the batter was under-beaten, or the baking powder was old. Make sure the butter is genuinely soft, beat for the full two to three minutes, and check the date on your baking powder.