Chocolate Cake Traybake!
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Thick chocolate cake traybake, with thick chocolate frosting! Perfect for parties, or occasions, or anything!
Traybake cakes
I haven’t done too many traybake recipes in my time, if you talk about cake style traybakes. The other side, the brownies, blondies, rocky roads etc I have done almost too many to count (whether the recipes made it to the blog or not), but cake wise? Only a few. This is for any particular reason to be honest, just because I never thought they were very ‘wow’.
To be fair, I am completely wrong. I often get requests for a cake like this, and I just haven’t really got round to it until now! When I posted my carrot cake traybake in March, it was SUCH a big hit! I honestly didn’t expect it, and it was a bit of a random one to plug some days up in the run up to Easter, but I regret not posting it sooner!
Requested recipe
I thought originally “oh its just a cake that you give out at a party, if you don’t want the centrepiece cake too big”, which is actually often a thing. People create a ‘cutting cake’ if they don’t want, or can’t have the actual wedding cake for example that massive. I just didn’t realise that people like making them at home so much!
When I have asked in the past for requests of recipes, I usually get really out there ones that are almost a bit too specific for my blog, or ones that I have done, or ones that I would happily do. But quite often or not, there are ones that are just basic bakes that I have managed to have not done already, or ones that completely passed my mind like this one!
Sponge
When starting this recipe I wanted to make sure that it was going to be delicious. When you have a traybake cake, there is NO WHERE to hide. You can’t layer it up and make it look that pretty, and its so big that its awkward to try and cover up in some way. I wanted to make sure that the cake was suitably fudgey, and delicious, like the ‘traybake cakes’ that you can buy for parties in the supermarket.
You can easily do it with a straight forward Victoria sponge style sponge but I just think if you really are only leaving it as is, with some frosting on top, then I wanted it a smidge denser to make it more delicious. I ended up basing it on my chocolate fudge cake recipe, but slightly altered to fit the tin better!
Coffee and buttermilk
Because this sponge uses coffee, and buttermilk, it creates the most wonderful thick gooey sponge that everyone wants to devour. Trust me, YOU CAN’T TASTE THE COFFEE, and it just enhances the chocolate flavour so I would 100000% recommend sticking with it! Honestly, you’ll regret it if you don’t. You can use actual espresso, or instant coffee etc, but anything dissolved in 125ml of water will do.
Frosting and decoration
The Frosting for the cake is also from my chocolate fudge cake recipe, as its just personally the best chocolate frosting on the planet ever. This is optional, you could easily use just melted chocolate, or a ganache type frosting, but I really wanted a good solid frosting instead that is usually a crowd pleaser, and from the comments I have received in the past, this is the frosting to choose! You can decorate it how you want, but I just went for some sprinkles and some small chocolate bits and it’s all done! Cut up into squares and enjoy! x
Chocolate Sheet Cake!
Ingredients
Cake
- 250 g dark chocolate
- 250 g unsalted butter
- 1 tbsp instant coffee
- 125 ml boiling water
- 200 g plain flour
- 50 g cocoa powder
- 1.5 tsp baking powder
- 1/2 tsp bicarbonate of soda
- 250 g caster sugar
- 250 g light brown sugar
- 4 large eggs
- 100 ml buttermilk
Frosting
- 250 g unsalted butter (room temp)
- 500 g icing sugar
- 50 g cocoa powder
- 100-125 ml evaporated milk
- 1 tsp vanilla extract
Extras
- Sprinkles
- Chocolate curls
Instructions
For the Cake
- Preheat your oven to 160/140C Fan, and line a 9x13" tin with parchment paper.
- In a heatproof bowl, microwave the dark chocolate & butter until melted – mine takes two minutes!
- Pour the coffee granules into 125ml boiling water and mix – add the coffee to the chocolate/butter mix and stir well until smooth!
- In a separate large bowl add the plain flour, cocoa powder, baking powder, bicarbonate of soda, golden caster sugar, and light brown sugar and mix well so the ingredients are all mixed with each other well!
- Mix the eggs with the buttermilk – add the chocolate mix & the egg mix to the dry ingredients and stir together, try not to over mix it – you don't need to use an electric mixer, just use a bowl and a spatula.
- Pour the mixture into the tin and bake in the oven for 50-60 minutes (can take a little longer in some ovens) once baked leave to cool in the tin and remove afterwards, or leave for 10-15 minutes and cool on a wire rack for a softer cake.
For the Frosting
- With an electric mixer with the paddle attachment, beat the butter until its very smooth and supple (couple of minutes)
- Gradually add the icing sugar & cocoa powder alternatively with the evaporated milk until all is incorporated and add the vanilla essence – beat for a couple of minutes so its extra smooth & creamy.
- The more evaporated milk you add the more runny it’ll be, and I have found about 100ml-125ml is perfect for me! Decorate your cake how you like and ENJOY!
Notes
- This cake will last for 3 days at room temperature.
- This is the cake tin I used
- I 100% would stick with using the coffee in the cake, you can't taste it, but it helps the chocolate flavour so is important.
- The cake can take longer to bake if its over mixed - be as gentle as possible with it.
- If you can't access buttermilk, you can make your own by using 100ml of FULL FAT milk, mixed with 2tbsp of lemon juice! It will look curdled but this is fine.
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J x
© Jane’s Patisserie. All images & content are copyright protected. Do not use my images without prior permission. If you want to republish this recipe, please re-write the recipe in your own words and credit me, or link back to this post for the recipe.
Hi, I was just wondering what brand of cocoa powder you use. Also, your recipes are amazing, they always come out delicious!
I use cacao barry as I buy large amounts (you can buy it on amazon)! And thank you!
Hi Jane! I have baked this cake so many times and it is such a treat, I get compliments all the time! I wanted to bake two of the tray bakes for work and a the Choc fudge loaf cake for work next week (it will use up all the buttermilk then!). My question was how can you convert this recipe to a 8 inch square tin or a 9 inch square tin? I had some leftover Nutella buttercream from 2 batches of cupcakes I baked a fortnight ago so I thought I could just slather it on a square cake so it doesn’t go to waste. Thanks and love all your recipes!
The best website to use for conversions I find is this one – http://www.cakebaker1.co.uk/apps-for-bakers/baking-tin-size-conversion-calculator/ x
Absolutely LOVE this traybake! I made it for my brother’s birthday in June and then for my sister’s birthday in October! It’s very dense and fudgey, almost like a brownie but is absolutely delicious!
Hi,
Using the coffee does this make the cake taste of coffee??
No not even slightly – honestly, just makes it taste more chocolatey!
Hi this is the second time I’ve tried making this cake .. both times it’s overflowed and I’ve baked it for around 1hour 15 minutes and it’s still quite raw in the middle and burnt on the edges .. what am I doing wrong ?
Are you sure you are using the correct size tin? Or it is deep enough? It definitely shouldn’t over flow so that may be the issue. x
So far so good. I have made the cake but I am not sure when to make the frosting. Should I make it half way through baking or whilst its cooling? And if I make it too early can I refrigerate it?
Always do it once the cake is out of the oven and cooling – you can’t decorate until it’s fulled cooled. x
Hello,
Thank you for an amazing recipe.
Please can I ask if you can use medium eggs instead of of large….. how many medium eggs would it be ?
Can you use any strength dark chocolate?
Personally I recommend 70% or darker when baking x
Absolutely delicious! Thank you!
Are you able to pipe the frosting into flowers onto the cake or will it be too soft?
I would say this frosting is too soft xx
Hi Jane I can only find a 9×12 traybake tin will this be ok to use with same measurements for ingredients? X
Yes that should okay, may take a smidge longer to bake x
Hi Jane
This looks delicious. Do you think it will work with fondant on top? I need to bake a Traybake with a theme for a party.
The frosting is quite soft, but if you are just putting a layer on top it may be okay..!
Hi can I use fresh cream as a substitute for the evaporated milk in the frosting
You can, but I would use less as it may soften the frosting too much (and then the cake technically needs storing in the fridge) x
Have been baking during lockdown for various charities and found you through one of the other bakers. Have made so many of your tray bakes for NHS and vulnerable people. They are all so good. Made this one yesterday. OMG so good. Want to make another one with the buttermilk and evaporated milk that I have left over. Does the cake freeze well? Obviously without the frosting..
Hey! Yes it does freeze well!! And I’m so glad! xx
Hi Jane!
Just 1 more question if that’s okay – Is there anything I can do or any changes you would reccomend i make to prevent the cake from coming out of the oven more like a moist brownie?? (Tastes AMAZING still – but wanted it fluffier like yours)
Thank you so much x
If a cake is dense it usually means it needed longer baking – although the texture of this sort of fudge cake is denser than a normal sponge! xx
Hi Jane!
Would i be able to double the ingredients to make this 2 tier? Or would you advise against this?
Thank you!
You would need to bake the sponges separately, and it is quite deep so that would be a whole lotta cake!! x
This is the 2nd cake I’ve made from this site. This one was just as good. It was lovely and I will make again. It didn’t last long and it was all adults no children. Next cake I’m trying is the biscoff cake for a birthday next week.