If you have ever needed a reliable chocolate cake that feeds a crowd without any fuss, this is it. Mary Berry’s chocolate traybake is one of those recipes that has stood the test of time for good reason. It is rich, moist, and topped with a smooth, glossy chocolate icing that sets just perfectly. Whether you are baking for a birthday, a bake sale, or a simple weekend treat, this recipe delivers every single time.
What makes it so popular is the all-in-one method, everything goes into one bowl, you beat it until smooth, and that is essentially the hard work done. No creaming butter for ten minutes. No tricky techniques. Just a dependable, delicious chocolate sponge cake that even beginner bakers can pull off with confidence.
Ingredients
For the Chocolate Sponge
- 4 tbsp cocoa powder
- 4 tbsp boiling water
- 225g softened butter or baking spread
- 225g caster sugar
- 275g self-raising flour
- 2 tsp baking powder
- 4 large eggs
- 4 tbsp milk
For the Chocolate Icing
- 150g plain dark chocolate, broken into pieces
- 3 tbsp water
- 150g icing sugar, sifted
- 75g softened butter
You will also need a 23 x 30cm (9 x 12in) traybake tin, greased and lined with baking parchment.
How to Make Mary Berry Chocolate Traybake
Follow these straightforward steps for a perfect result every time.
- Preheat the oven to 180°C (160°C fan / Gas 4). Grease your traybake tin and line the base with non-stick baking paper.
- Bloom the cocoa by mixing the cocoa powder with the boiling water in a large bowl. Stir until you get a smooth, thick paste and allow it to cool slightly. This step intensifies the chocolate flavour significantly.
- Make the batter by adding the softened butter, caster sugar, self-raising flour, baking powder, eggs, and milk directly into the cocoa mixture. Beat everything together with an electric hand whisk or stand mixer until the batter is smooth, fluffy, and well combined.
- Fill the tin by spooning the batter into the prepared tin. Use a spatula to level the surface evenly so the cake bakes at a consistent depth.
- Bake in the centre of the preheated oven for 30 to 35 minutes, or until the sponge has risen and springs back lightly when pressed in the middle with your fingertip.
- Cool completely in the tin before adding any icing. Patience here is important, icing a warm cake will cause it to melt and slide off.
- Make the chocolate icing by gently melting the dark chocolate with the water in a heatproof bowl set over a pan of simmering water (or in the microwave in short bursts). Once melted and smooth, remove from the heat and allow to cool slightly. Beat in the sifted icing sugar and softened butter until the icing is thick, glossy, and spreadable.
- Ice the cake by spreading the chocolate icing evenly over the cooled sponge. Leave it to set before slicing into squares.
Tips
How Do I Keep the Sponge Moist?
The key to a moist chocolate sponge is not overbaking it. Check the cake at the 30-minute mark by pressing the centre gently, it should spring back without leaving an indent. Also, blooming the cocoa powder with hot water before mixing adds depth and moisture. Using baking spread straight from the fridge rather than softened butter also gives a slightly softer crumb.
Why Is My Icing Too Thick or Too Thin?
If your icing is too thick, add a teaspoon of warm water at a time and stir until it loosens to a spreadable consistency. If it is too thin and runny, add a little more sifted icing sugar until it thickens up. Always sift the icing sugar before using it, this prevents lumps forming in the finished icing.
Can I Make This Cake Ahead of Time?
Yes, absolutely. The un-iced sponge can be baked a day in advance and stored wrapped in an airtight container at room temperature. Ice it the following day before serving. Once iced, the traybake keeps well for several days, making it a brilliant option for planning ahead before events.
Serving Suggestions
This chocolate traybake is incredibly versatile when it comes to serving. Here are a few ideas:
- Slice into neat squares and serve as a teatime treat alongside a strong cup of builder’s tea or a flat white.
- Serve warm squares with a scoop of good vanilla ice cream for a simple, crowd-pleasing pudding.
- Add a dollop of lightly whipped cream on the side for a more indulgent dessert.
- Pair with fresh strawberries or raspberries for a fruity contrast that cuts through the richness of the chocolate.
- Decorate with chocolate shavings, sprinkles, or a light dusting of icing sugar to make it look celebration-ready.
For a flavour variation, try adding the zest of an orange to the batter or stirring a handful of dark chocolate chips into the mix before baking.
Storage
Room Temperature
Once iced and set, store the traybake in an airtight container at room temperature for up to 3 days. Keep it away from direct sunlight or heat sources to prevent the icing from softening.
Refrigerator
For longer storage, place the traybake in an airtight container in the refrigerator for up to 5 days. Remove it from the fridge around 30 minutes before serving so it comes back to room temperature, the sponge will be much softer and more enjoyable to eat.
Freezing
The un-iced sponge freezes exceptionally well for up to 3 months. Wrap it tightly in cling film, then a layer of foil, and freeze flat. Thaw at room temperature for a few hours before icing and serving. If you want to freeze individual slices already iced, wrap each piece separately in cling film and foil and freeze for up to 2 months.
Nutrition
The following is an approximate guide per serving, based on 15 slices. Actual values will vary depending on exact ingredients used.
| Nutrient | Per Slice (approx.) |
| Calories | 320 kcal |
| Carbohydrates | 38g |
| Sugar | 26g |
| Fat | 17g |
| Saturated Fat | 10g |
| Protein | 4g |
| Fibre | 1.5g |
| Salt | 0.3g |
These figures are intended as a general reference only.
FAQ’s
Can I use cocoa powder instead of melted chocolate for the icing?
Yes, if you prefer a simpler icing, you can use sifted cocoa powder in place of melted chocolate. Mix it with icing sugar, softened butter, and a little milk to create a thick, fudgy chocolate buttercream instead.
What size tin should I use for this recipe?
A 23 x 30cm (9 x 12in) traybake tin is the ideal size. Using a smaller tin will result in a thicker sponge that may need extra baking time, while a larger tin will produce a thinner cake that bakes more quickly.
Can I make this recipe gluten-free?
Yes, simply swap the self-raising flour for a good-quality gluten-free self-raising flour blend. Add an extra half teaspoon of baking powder to help with the rise, and the result is a very similar texture.
Why did my sponge sink in the middle?
A sunken centre is usually caused by underbaking or opening the oven door too early. Make sure the oven is fully preheated before the tin goes in, and resist opening the oven for at least the first 25 minutes of baking.
Can I use margarine instead of butter?
Yes, baking spread or margarine works perfectly in this recipe. Mary Berry herself often uses baking spread as it creates a softer, more tender crumb than butter.
Does this recipe work for cupcakes?
Yes, you can use the same batter to make approximately 18 to 20 cupcakes. Reduce the baking time to around 18 to 22 minutes and check them early using the springback test.
Can I add chocolate chips to the batter?
Absolutely. Stirring 100g of dark or milk chocolate chips into the batter before baking adds extra pockets of melted chocolate throughout the sponge and gives the traybake a more indulgent finish.
Final Thoughts
Mary Berry’s chocolate traybake is exactly the kind of bake that earns its place in your permanent recipe rotation. It is straightforward enough for a weeknight bake, impressive enough for a celebration, and reliable enough to trust the first time you make it. The all-in-one sponge method takes the stress out of baking, and the rich chocolate icing ties the whole thing together beautifully.
Once you have made it once, you will understand why this recipe has remained a household favourite for decades. Give it a go, slice it generously, and enjoy every square.
