Chocolate Chunk Buttermilk Cake with Whipped Mars Bar Frosting

Chocolate Chunk Buttermilk Cake with Whipped Mars Bar Frosting


Hola everybody! A simple yet indulgent afternoon tea cake for you guys today. This cake is really great for using up leftover buttermilk from that time you went to the supermarket, saw it, adamant to make buttermilk pancakes but oddly never got round to it.. Or maybe when you intended to make the juiciest fried chicken imaginable but simply ordered take out instead, because who really has time to let chicken marinade in buttermilk? Or maybe it was from that time you picked up buttermilk by accident when reaching for the double cream to drown your sorrows in? Either way, by accident or intention, this buttermilk cake is your friend. If you don’t have any spare buttermilk lying around, it’s a pretty good excuse to go and pick some up to be honest.

If you’re sat there wondering what the heck buttermilk even is, then I really urge you to have a look for it in the supermarket! Most places stock it these days but if they don’t, apparently, according to the internet, the same amount of milk with a teaspoon of lemon juice mixed together and sat on the counter for five minutes also works. I have yet to try the faux buttermilk option, but I will update you whenever I do 🙂

For the cake

160g room temperature butter

220g golden caster sugar, or regular caster sugar

2 large room temperature eggs

2tsp vanilla extract

200g plain flour

100g self-raising flour

¼ tsp bicarbonate of soda

220ml buttermilk

250-300g milk or dark chocolate

For the mars bar frosting

150g salted butter, room temperature

300g icing sugar

5tbsp cocoa powder

2-3tbsp milk

2 small mars bars (or one of those long bars that comes with two mini ones in)

1) Preheat oven to 160°CFAN and grease and line a suitable cake tin. I used a 20cm square tin this time because you know, square cakes need love too. But you can use an 8” round tin, that’s absolutely fine.

2) Sift both flours and bicarb together in a bowl and leave to one side

3) Cream the butter and sugar until fluffy using an electric mixer. Add the eggs one at a time, and beat to combine. Then add the vanilla and give it a final beat.

4) Turn the mixer on low, or use a wooden spoon to add about half the flour followed by half the buttermilk. Repeat using the rest of the flour and buttermilk but be careful not to overmix. A few lumps are okay!

5)Chop the chocolate into chunks and fold them in to the cake mixture evenly dispersing them. Pour in to the tin and leave it in the oven for about an hour. Give or take 10 minutes depending on the size of your tin. Check it regularly after about 50 minutes and once a skewer comes out clean, it’s done.

6)Turn the cake on to a wire rack and let it cool. This cake freezes really well and is really perfect for tea time so don’t be afraid of making it when you have time and freezing it for when you need it. Be sure to take it out of the freezer about 7 hours before you need to eat it!

The star of the show really is this whipped mars bar frosting, it complements the sourness of the buttermilk in the cake perfectly and has the most unique chew to it from the mars bar!


1) Whip the butter for about two minutes on high speed.

2) Chop in to smaller pieces and melt the mars bar in the microwave in two 20 second blasts. It doesn’t take long until it becomes gooey and sticky. Set it aside to cool.

mmm melty mars bar…

3) Sift in the icing sugar and cocoa powder in to the butter and on low speed give it another mix until you have a crumbly consistency.

4) Add milk by the tablespoon sparingly, beating until the frosting just comes together.

5) Once the mars bar is cooler (it will still be warm to the touch) add it to the rest of the frosting. The heat slightly melts the butter in the frosting loosening it up so be careful not to add much milk during the initial stage!

6) Spread it on top of your cake nice and thickly for that perfect frosting to cake ratio, slice it up and enjoy.

Store the cake in the fridge, as the frosting is even more magical when it’s cold 🙂



Recipe adapted from Ina Garten’s Barefoot Contessa “Plain pound cake”

Unfortunately for me, I’m not free from the wrath of exams for another week and a half or so! It seems super close, right??? Wrong. I really don’t know how my brain is supposed to expand by like 70% before then but let’s all hope for the best!

P.S This week’s Instagram bakes are looking faaaaantastic as usual!

Thanks to @charliegill22 and @_hxva!

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