Anna Louise Every baker needs a reliable chocolate traybake in their repertoire. Not a complicated layered cake. Not a fussy showstopper. Just a deeply chocolatey, moist, beautifully simple traybake that comes together quickly, feeds a crowd, and makes everyone genuinely happy.
Mary Berry’s chocolate traybake is exactly that. The sponge is rich and tender — made with both cocoa powder and boiling water, which blooms the cocoa and gives a depth of chocolate flavour that is far more intense than cocoa alone would produce.
The fudge icing on top is smooth, glossy, and deeply chocolatey — it sets to a soft finish that cuts cleanly and tastes extraordinary.
This is the traybake I make for birthday parties, for school bake sales, for any occasion where I need to feed twenty people something wonderful without spending the entire day in the kitchen.
It is one of Mary Berry’s most trusted recipes and one of the most popular bakes on this site for very good reason.
What Makes This Chocolate Traybake So Good?
Boiling water blooms the cocoa. Adding boiling water to cocoa powder before it goes into the batter is a technique that transforms the flavour. The heat releases the full aromatic compounds in the cocoa, producing a chocolate flavour that is deeper, richer, and more complex than cocoa mixed with cold liquid. This is the step that makes this traybake taste genuinely special.
The all-in-one method. Everything into one bowl, beaten together. No separate bowls, no creaming, no complexity. Reliable, quick, and consistently excellent.
The fudge icing. This is not a simple glacé icing — it is a proper fudge icing made with butter, icing sugar, cocoa, and a small amount of warm water, beaten until smooth and glossy. It sets to a soft, slightly yielding finish that is completely wonderful and cuts cleanly without cracking.
Ingredients for Mary Berry Chocolate Traybake
For the Chocolate Sponge
- 225g unsalted butter, softened
- 225g caster sugar
- 275g self-raising flour, sifted
- 2 tsp baking powder
- 4 large eggs, at room temperature
- 4 tbsp whole milk
- 50g good quality cocoa powder, sifted
- 4 tbsp boiling water
- 1 tsp vanilla extract
For the Chocolate Fudge Icing
- 175g unsalted butter, softened
- 350g icing sugar, sifted
- 40g good quality cocoa powder, sifted
- 4–5 tbsp warm water
- 1 tsp vanilla extract
To Decorate (Optional)
- Chocolate sprinkles or vermicelli
- Chocolate buttons or Smarties for a children’s party version
- A dusting of cocoa powder for a more elegant finish
How to Make Mary Berry Chocolate Traybake — Step by Step
Step 1 — Preheat and Prepare
Preheat your oven to 180°C / 160°C fan / Gas 4. Grease a 30x23cm traybake tin and line with baking parchment, leaving overhang at the sides.
Step 2 — Bloom the Cocoa
In a small bowl, mix the cocoa powder with the boiling water until you have a smooth, thick paste. The cocoa will smell intensely chocolatey at this point — this is the blooming working. Leave to cool for two to three minutes before adding to the batter.
Step 3 — Make the Batter
Place the softened butter, caster sugar, sifted flour, baking powder, eggs, milk, and vanilla extract into a large mixing bowl. Add the bloomed cocoa paste. Beat everything together with an electric hand whisk for two to three minutes until smooth, well combined, and slightly lighter in colour. Scrape down the sides and give it one final beat.
The batter will be a deep, gorgeous chocolate brown. It should be thick but pourable — not as stiff as a standard sponge batter because of the cocoa paste.
Step 4 — Bake
Pour the batter into the prepared tin and spread evenly to the corners. Level the top carefully — an even surface means an even bake.
Bake on the middle shelf for 35 to 40 minutes until the sponge is risen, the top feels firm to a light touch, and a skewer inserted into the centre comes out clean. Do not overbake — a chocolate sponge dries out quickly and loses that wonderful fudgy quality that makes this traybake so good.
Leave to cool completely in the tin before icing. A warm sponge will melt the fudge icing immediately.
Step 5 — Make the Chocolate Fudge Icing
Beat the softened butter alone for three to four minutes until very pale and fluffy. Add the sifted icing sugar and cocoa powder in two batches, beating well after each addition. The mixture will look very dry and crumbly at first — this is normal.
Add the vanilla extract and warm water, one tablespoon at a time, beating well after each addition until the icing comes together into a smooth, glossy, spreadable consistency. The finished icing should be thick enough to hold its shape when spread but soft enough to spread easily with a palette knife. Add more water a teaspoon at a time if it is too stiff.
Step 6 — Ice the Traybake
Spread the chocolate fudge icing generously over the completely cooled sponge using a palette knife. Work with long, confident strokes to get a smooth, even finish. Or create gentle swirls for a more relaxed, informal look — both are equally good.
Decorate as you like — chocolate sprinkles for a children’s party, a dusting of cocoa for something more grown-up, or leave plain for the most elegant finish of all.
Step 7 — Cut and Serve
Leave the icing to set for 20 to 30 minutes before cutting into squares. Use a sharp knife and wipe it between cuts for the cleanest edges.
My Top Tips for the Best Chocolate Traybake
Do not skip blooming the cocoa. This single step makes the biggest difference to the chocolate flavour of this traybake. Mixing cocoa with boiling water before it goes into the batter intensifies the flavour dramatically. It takes 30 seconds and transforms the result.
Use good quality cocoa powder. With only one source of chocolate flavour in the sponge, the quality of the cocoa matters. A good quality, high-fat cocoa powder — Green and Black’s, Callebaut, or a good supermarket own-brand — produces a significantly better result than cheap cocoa. It is worth spending slightly more.
Do not overbake. A chocolate traybake that is one minute too long in the oven goes from moist and fudgy to dry and disappointing very quickly. Check at the 35-minute mark. The skewer should come out clean but the sponge should still feel slightly tender rather than completely firm.
Cool completely before icing. I say this and yet it is tempting every single time to ice too early. Even a slightly warm sponge melts the fudge icing and you end up with it running off the edges. Complete patience here is essential. At least an hour.
Beat the butter well before making the icing. Four minutes of beating the butter alone before adding anything else gives you a fudge icing that is light, smooth, and beautifully glossy rather than heavy and dense. Do not rush this step.
Score the icing before it fully sets if serving to children. Scoring the icing lightly with a knife after 10 minutes of setting gives you cutting guides that make portioning much easier — particularly helpful when cutting into small squares for a party.
Serving Suggestions
Cut into squares and served at room temperature — this needs nothing alongside it. For a birthday party, decorate with candles and serve with a scoop of vanilla ice cream. For a more grown-up occasion, a small square with a cup of good strong coffee is a very satisfying thing.
How to Store Mary Berry Chocolate Traybake
At room temperature: Store in an airtight container for up to 4 days. The sponge stays moist and the icing stays glossy.
In the freezer: Cut into squares, wrap individually in cling film, and freeze for up to 3 months. Defrost at room temperature for an hour. The fudge icing softens slightly on defrosting but the flavour is completely preserved.
Mary Berry Chocolate Traybake
Ingredients
Method
- Preheat oven to 180°C / 160°C fan / Gas 4. Grease and line a 30x23cm traybake tin.
- Mix cocoa powder with boiling water until a smooth paste. Cool for 2–3 minutes.
- Place butter, caster sugar, flour, baking powder, eggs, milk, vanilla, and cocoa paste into a large bowl. Beat with electric whisk for 2–3 minutes until smooth and combined.
- Pour into prepared tin. Spread evenly to corners. Bake 35–40 minutes until risen and a skewer comes out clean. Cool completely in tin.
- Beat butter alone for 3–4 minutes until very pale. Add icing sugar and cocoa in two batches. Add vanilla and warm water one tablespoon at a time, beating until smooth and glossy.
- Spread fudge icing over cooled sponge. Decorate as desired. Leave to set 20–30 minutes. Cut into squares with a sharp knife.
Notes
Frequently Asked Questions About Mary Berry Chocolate Traybake
Can I use melted chocolate instead of cocoa powder?
You can add 100g of melted dark chocolate to the batter alongside the cocoa for an even richer result — reduce the boiling water to 2 tablespoons if doing this. Using melted chocolate alone instead of cocoa changes the texture of the sponge significantly — it becomes denser and more brownie-like. Both are good but they are different things.
Why did my chocolate traybake sink in the middle?
Usually caused by opening the oven door too early, underbaking, or using too much baking powder. Wait until at least 30 minutes have passed before opening the oven, and measure your baking powder carefully.
Can I make this traybake without the fudge icing?
Yes — the sponge is wonderful on its own, dusted with icing sugar. You could also top it with a simple chocolate ganache instead — heat 150ml double cream, pour over 150g finely chopped dark chocolate, stir until smooth, and spread over the cooled traybake.
Can I add coffee to the chocolate traybake?
Yes — a teaspoon of instant espresso powder dissolved in the boiling water before blooming the cocoa adds a depth to the chocolate flavour without making it taste of coffee. It is a brilliant addition and one I use regularly.
Why is my fudge icing grainy?
The icing sugar was not sifted, or the butter was too cold. Always sift the icing sugar and cocoa together before adding, and make sure the butter is genuinely soft — room temperature — before you begin beating.
Can I make this as a round birthday cake?
Yes — divide the batter between two greased and lined 20cm round sandwich tins and bake at the same temperature for 25 to 30 minutes. Use the fudge icing to sandwich and top the cake. It makes a wonderful birthday cake.
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