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a wedge of frosted chocolate layer cake on a white plate in front of a cake stand with the rest of the cake
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4.32 from 16 votes

Simple Steam Oven Chocolate Cake

This steam oven chocolate cake uses two bowls and a whisk. No melting, no beating, and, if you’re lazy like me, not even any sifting. The key is baking the cake in layers for a fast, even cook which results in a soft, springy and even texture.
Prep Time30 mins
Cook Time22 mins
Total Time52 mins
Course: Dessert
Cuisine: American
Keyword: chocolate cake, sour cream chocolate frosting, steam oven, steam oven cake recipe, steam oven chocolate cake
Servings: 12
Calories: 643kcal


For Sour Cream Chocolate Frosting


  • Grease and line the bases of two 9 inch/22cm cake tins (or one if that’s all you have – you can turn out the first cake, pour the batter in for the second and bake in two batches. The second cake won’t rise quite as much because the batter sits around, but the difference is negligible). I have these great cake tin liners which I love and try to always keep around.
  • Preheat your oven to 320⁰F/160⁰C, combination steam setting. If your oven has variable steam settings, use 60% (if not, don't worry! Just set to combi steam at the correct temperature and the oven will work out the steam level for you).
  • Put all the dry ingredients in a large bowl and give them a whisk to combine. I don’t sift but if your baking soda in particular is lumpy, give it a quick sieve so you don’t end up with fizzy lumps in your cake.
  • Put all the wet ingredients except the water into another bowl and whisk to combine. Pour the wet mixture into the dry mixture and whisk until it’s just smooth. Add the water and mix gently to incorporate.
  • Divide the batter between your two tins and bake them for about 22 minutes, or until they’re springy and test clean with a skewer. Leave to cool in tins for 5-10 minutes before turning out to cool completely.

Sour Cream Chocolate Frosting

  • Melt dark chocolate, then stir in room temperature full fat sour cream until it’s incorporated and you have a smooth, shiny mixture. You can use this straightaway as a pouring consistency frosting (if you only want a thin coating), or wait for it to cool and thicken slightly before spreading over the cooled cakes.



This makes one 22cm/9” cake with two layers. If you’d like to make it in a smaller tin I’d suggest splitting the batter in thirds and adjusting the cooking time down a few minutes, because the deeper the batter, the higher the risk of the dreaded cracked top and too-dense texture.
You’ll see there is no chocolate in the cake, only cocoa. Use the very best you can afford – my absolute favourite is the Barry Cacao Extra Brute. Yes, it comes in a big bag, and yes, I buy it in that quantity. It keeps for ages in a cool, dark place and I find I get through a bag or two a year. You’ll taste the quality of the cocoa in the finished cake and I always figure there’s no point wasting your time in the kitchen for inferior baked goods.
I’ve called for milk + lemon juice in this recipe because it’s what I most often have available, but if you have buttermilk hanging around in your fridge, use that instead as your acidic component.  
Don’t be tempted to use ‘light’ sour cream, the water content means your frosting might seize.
The frosted cake will keep, covered, for about 4 days.


Serving: 1slice | Calories: 643kcal | Carbohydrates: 62g | Protein: 7g | Fat: 42g | Saturated Fat: 29g | Cholesterol: 43mg | Sodium: 357mg | Potassium: 433mg | Fiber: 6g | Sugar: 36g | Vitamin A: 240IU | Vitamin C: 0.4mg | Calcium: 97mg | Iron: 6mg