The chocolate slab cake, which I posted about nearly a year ago, has been the most widely made recipe on our blog.
I think that’s because it’s easy to make and results in a large quantity of chocolate cake, without the need for any fancy icing or too much fuss. It’s perfect for a party, and has the simplicity of a packet mix (almost!), but with really great ingredients – Belgian chocolate, real butter and eggs, and no funny preservative numbers. Because it’s based around a devil’s food cake recipe, the resultant crumb is moist and tender, and as an added bonus, it slices cleanly into neat portions for sharing. Here it is cut into baby 3cm squares, so you can see what I mean…
Pete describes it as the chocolate cake equivalent of those little wrapped bars of vanilla ice cream we used to buy when we were kids – unpretentious and comforting to eat in large quantities.
For me, it’s a communal cake, which is why I love baking it so much. I made a slab yesterday, and a piece has gone to the neighbours, another piece is on its way to the school music department and a third piece will go to my friends at the cheese shop when I make my way over there later on today.
Joanna in Bristol asked me for metric measurements, so I weighed up my ingredients as I was making this yesterday. Here they are…
Cake
- 440ml boiling water
- 170g dark chocolate, chopped finely (we use Callebaut callets)
- 110g unsweetened cocoa
- 300g plain (all purpose) flour
- 2 teaspoons bicarbonate of soda (baking soda), sifted
- good pinch salt
- 285g unsalted butter, softened
- 380g brown sugar
- 4 large eggs
- 2 teaspoons vanilla extract
Icing
- 100g dark chocolate callets, or finely chopped chocolate
- 100g unsalted butter
- 100g icing sugar, sifted (it’s important to sift, or you’ll get lumpy icing)
- 60ml milk
I’ve also updated the lists on the original post, which has the instructions for putting the cake together. I hope you’ll try it out. In our house, having one of these cakes on the go makes everyone feel just that little bit better.
Fig Jam and Lime Cordial 
wow that looks incredibly moist! must make!
how big exactly is ‘a large quantity’? half-sheet? 13X9?
went to the other post and got the answer, which i should have done before asking!!!!
You are a dear and I think I need to make one of these this afternoon, only I might make a half size one to start with!
I’m surprised that 2 cups of flour came out to be 320g – most of the conversion tables I’ve seen give a cup of flour to be something between 100 and 125g. 160g seems a big difference!
Suelle, it puzzles me too. I just went and measured again, and it was 145g per cup. It seems to vary enormously depending on ambient humidity. Having said that, it was 158g when I made the cake a couple of days ago, so I rounded to 320g for the two cups. I’ve seen weight charts that specify a cup of flour at 125g and others that say 155g, and yet others that draw a distinction between sifted and unsifted. Oh how I wish Americans would write recipes in weight measures instead of cups!
For what it’s worth, the original recipe called for two cups of cake flour, which I don’t have easy access too over here.
On reflection, I’m going to pull back the recommended flour weight just a little. I think the flour I use (which I buy direct from the miller in 25kg bags) is quite heavy. Perhaps it has a higher hydration, or perhaps storing it in the freezer makes it heavier. Thanks for drawing this to my attention, Suelle…
I dislike the awkwardness of using cups as much as the potential for inaccuracy – it’s OK to dip a cup into a large sack of flour, but trying to get a cup-full out of a small 1.5kg bag of flour (or an even smaller bag of sugar) without making a mess is not easy. I convert cup recipes to weights, but have worried about the ‘real’ weight of flour for a while now!
We don’t have cake flour in the UK either, although I think there are very expensive branded flours available which claim to be more suitable for cake making. I use regular supermarket own brand flour, but rarely make really delicate cakes which might benefit most from cake flour.
Suelle, as I mentioned below, I’m going to work on 150g to a cup from now on. This has been a really useful discussion – thanks! :)
A cake for sharing has got to be the best. This looks so delicious and moist. I’ve going to a herbal remedy course on Saturday and need to “bring something to share”. I had some cupcakes in mind, but now thinking this might be a better option.
It’s definitely less fiddly than cupcakes, Choclette! :)
I’ve made this cake twice now and it’s wonderful. I know I said it before, but again – Thanks!
Meaghan, it’s lovely of you to leave another comment about it – thank you! I hope you’re feeding hordes of people with it! :)
Oh wow. This looks amazing. Just in time for my small boy’s 3rd birthday celebrations. Thanks for the post.
It’s perfect for a party, Kirsten, but quite dark. I’m not sure how well it sits with little palates, but having said that, it always seems to disappear.. :)
It’s easiest if you serve it straight out of the roasting tray!
Gosh that looks good. Must try it soon….only problem is that I am likely to eat the entire slab!! Warm chocolate cake that actually tastes of chocolate, that is not overly rich or fancy….mmm…my idea of perfection!
Your chocolate slab cake looks delicious!
I think i just found what I’m making for my grandma’s birthday this weekend :P
Thanks Kristy, hope she enjoys it! :)
I love the look of your cake and can see that it has the just the kind of tender crumb and I like.
Odd about the flour weight, but I think you’re right about the differences in weight being attributable to temperature, humidity and storage, as well as the age of the flour, perhaps. The other day I was weighing out 1 cup of American all-purpose flour and found that if I scooped it out of the bin 1/2 cup at a time, it weighed less than if I scooped it out in a 1 cup measure (in which the flour was more tightly packed, I would presume).
Dorie, thank you, I’m sure you’re right. I wonder if there’s also geographical differences? I’ve been reading recipes in my Oz cooking magazines, and noticed that they seem to work on a standard cup of flour weight of 150g, which is higher than the US, which seems to work on 125g/4oz per cup. Our standard cup measure is a tiny bit bigger too – 250ml vs 240ml in the US. I wish I understood more about this – I might have to bend the ear of Kevin the miller and see what I can find out…
PS. Pete said the same thing as you did, that it depended how you scooped. I think he was implying that I’m heavy-handed.. :)
Guess what the kids will be eating for morning tea at school tomorrow? Also have a PA morning tea, so that’s two birds with one cake!
That’s fantastic, Sharron, thanks for letting me know! I’m cutting a slice for the music teacher right now. Our slab from three days ago is still going – we’ll get dessert out of it tonight as well!
i wish everyone would just adopt the metric system and save us all this headache. i’m having the same problems when i translate back and forth. i find julia child’s conversion table reliable, but i’ve had the same thing happening – in two consecutive days, same cup yielded different weights when measured in grams… and that whole story with sifting in the cup or after scooping! exhausting, isn’t it! so according to julia, one cup scooped is 140 gr, and one cup sifted is 100 gr. i get different opinions every day.
Dana, thank you for that! If the great Julia says 140g, then I don’t feel so bad working on 150g!
This sounds like the perfect chocolate cake. Thanks for sharing :)
Thank you, O Cake Mistress! :D
Hi Celia,
Aside from your marvelous cake, I loved your reference to those wrapped ice-cream “bars.” I’d forgotten about them – I haven’t had ice-cream for years – but they were the staple of childhood dessert treats. Thanks for sparking the memories! Are they still around?
On the flour, I’ve tended to assume 140-150g flour per cup when there is a need to convert a recipe etc.,
Craig, I haven’t seen them in ages! I used to love them with the wafers, but Pete just ate them straight.
Now…any chance of persuading you to bake some cottage loaves with us? :D
Celia – just noted your reply to Suelle and you talk of freezing your flour. I was just wondering recently if I could freeze flour so I can buy it in bulk. I’m assuming it works then?
Choclette, I freeze all my flour – in fact, I have an old freezer that I bought from a friend a lifetime ago for $100 which is now a dedicated flour freezer! You need to package it in good plastic bags though, because paper bags tend to soak through and the flour can get clumpy. Also, don’t use freezer bags – they’re quite thin and can break over time. I bought bags from my local deli – the ones they use to vacuum seal their food in. I also take the flour out and let it come to room temperature in the bag before using. Having a freezer has meant I can buy flour in 75kg quantities! :D
I use large zip lock bags from the supermarket and they work fine too.
Thanks O Convergent One. I was just logging back in to say that…hahaha…
Celia – I did make this cake for the course today and boy did it go down well. Everyone loved it and you were right it did cut very well. As it was a herbal course I used lavender rather than vanilla as the flavouring, which also went down well and I used a chocolate and yogurt topping rather than the one you did. I wouldn’t quite go as far as to say it was as easy a cake mix (although I’ve never actually used a cake mix so a bit of an assumption on my part) but it certainly wasn’t difficult and it did come out so well. So thank you. I shall be posting about it in the next few days.
Choclette, thanks for letting me know! Yeah, I thought afterwards that suggesting it was that “easy” might have been a stretch, but I don’t think it’s hard, just a little fiddly. And if you factor in that you have to know how to drive a car to buy a packet mix, well then… :D
The 7 boys here yesterday gave it 10 out of 10. Hx
Fantastic! Thanks for letting me know…. :)
Hi there, this is a great looking recipe! Am thinking of using it for a weekend away with friends, but I’d have to cook it at home on a Thursday evening (or Friday morning) and serve it on Saturday night. How do you think it would hold up after possibly 48 hours?
Hi Donina,
The cake is usually fine for a few days, although it rarely lasts that long. When we bake it, the neighbours usually come over with plates to take a share home. :) We weren’t invited to the 21st, but I think the slab cake would easily feed a dozen people with healthy appetites!
Cheers, Celia
Forgot to ask: Using your baking tin dimensions, roughly how many people would it feed? ie. how many 20 year olds did it feed at the 21st?
Many thanks :-)
Do you know how many times I have printed this out?!! Making it for ten 9yr olds tomorrow!