150 Hour Chocolate Cake

Right, so I’ve made some long recipes before — 100-hour brownies, 100 hour cookies… but this 150 hour chocolate cake recipe might just take the crown.

Yep, this is the 150-hour chocolate cake. Or at least, my version of it.

The original recipe comes from Alvin Zhu — you can watch his version here — and, unbelievably, there’s no written recipe anywhere. So I tried to piece it together from his video, a bit of guesswork, and a lot of fridge space.

The idea

This cake takes almost a week to make. You brown butter and “fat-wash” it with bourbon, infuse cream with coffee beans, rest the batter for two days, and stack it all into a glossy mousse-covered tower that looks like it’s come out of a high-end patisserie.

It sounds ridiculous. It is ridiculous. But it also might be the best chocolate cake I’ve ever had.

The 150 Hour Chocolate Cake Recipe Process

This 150 hour chocolate cake recipe involves seven days of infusing, resting and layering pure chocolate madness.

Day one kicked off with browned butter and bourbon — apparently that’s called fat-washing, but really it’s just butter meeting booze in the fridge. Then I soaked coffee beans in cream for two days, hoping I’d have enough left once the beans had finished drinking most of it. (Pro tip: make a bit extra. They’re greedy.)

Two days later, the butter’s solidified, the bourbon’s clarified, and you make a cake batter that sits in the fridge for another two days. I know. Every time I opened the fridge door, this project stared back at me like, “Still here, mate?”

Day five was where it all came together — baking the cakes, whipping up a massive bowl of chocolate mousse (I used milk chocolate, not dark, because apparently I like to live dangerously), and brushing each sponge with a hot-chocolate soak before stacking it into a tall, wobbly tower.

Then it’s back in the fridge again, because of course it is.

Finally, on day seven, the whole thing gets coated in more mousse, covered in ganache made with that coffee-infused cream, and finished with a wall of milk chocolate chips.

It’s absurdly rich, properly indulgent, and far too good to rush.

Was it worth it?

If you’re brave enough to try this 150 hour chocolate cake recipe yourself, make sure your fridge is ready for it.

It’s the kind of thing you have one bite of and instantly forget how many days it took to make. I didn’t even need to write down measurements in the end because I could practically taste what was right. (That’s my story, anyway.)

If you fancy punishing your fridge and rewarding your taste buds at the same time, give it a go — or, if you’d like something slightly less life-consuming, maybe try my 100-Hour Brownies first. They’ll only ruin your weekend, not your whole week.