Instead of the typical creaming process, in which butter and sugar are first whipped together, here the butter is mixed into the dry ingredients to completely coat them with fat, mimicking commercial cake mix with its fork-tender, light-as-air texture.
It’s crucial that everything be at room temperature here. Don’t skimp on this step! If you haven’t had the chance to prepare ahead of time, you can gently heat the buttermilk while you preheat the oven.
Overview
Prep time
1 hr
Cook time
30 mins
Serves
Makes 1 x 23cm cake
Ingredients
Non-stick cooking spray, to grease the tins
235ml buttermilk, at room temperature
1 tsp vanilla extract
190g plain flour whisked with 60g cornflour
250g granulated sugar
1½ tsp baking powder
½ tsp bicarbonate of soda
170g unsalted butter, at warm room temperature (18-24C), cut into 1 tbsp-sized pieces
2 tbsp flavourless oil (such as corn or vegetable oil)
3 medium eggs, at room temperature, lightly whisked
Rainbow hundreds and thousands or sprinkles, for decorating (optional)
For the soured-cream fudge icing
230g unsalted butter, cut into pieces
115g plain dark chocolate, finely chopped
240g icing sugar, sifted
70g cocoa powder, sifted
320g soured cream, straight from the fridge
2 tsp vanilla extract
Method
Step 1
Adjust an oven rack to the centre position and preheat the oven to 180C/160C fan/gas mark 4.
Step 2
Coat 2 x 23cm round cake tins with non-stick cooking spray, line the bottoms with rounds of baking parchment, then spray the parchment and set the tins aside.
Step 3
Pour 235ml buttermilk into a jug. Add 1 tsp vanilla extract and stir to combine. Set aside.
Step 4
In a stand mixer fitted with the paddle attachment, combine 190g plain flour whisked with 60g cornflour, 250g granulated sugar, 1½ tsp salt, 1½ tsp baking powder and ½ tsp bicarbonate of soda, and mix on a low speed for 30 seconds.
Step 5
Add 170g unsalted butter and continue beating for about 2 minutes until the mixture resembles breadcrumbs.
Step 6
Add 2 tbsp flavourless oil and continue mixing until it comes together into a pasty dough.
Step 7
Increase the speed to medium and gradually add 3 beaten eggs in 3 batches, beating for 20 seconds after each addition to allow the eggs to incorporate.
Step 8
Use a spatula to scrape down the sides and bottom of the bowl, as well as the paddle attachment.
Step 9
Return the mixer to medium and add the buttermilk mixture.
Step 10
Beat just until evenly combined and no thick lumps remain.
Step 11
Use a spatula to scrape down to the bottom of the bowl to make sure that all the dry ingredients are incorporated.
Step 12
At this point, the batter should be light, shiny, creamy and beautifully emulsified. (If you are worried about the emulsion breaking, remove the bowl from the mixer, add a few chips of ice and whisk rapidly by hand to stabilise the mixture.)
Step 13
Evenly divide the batter between the tins.
Step 14
Transfer to the centre rack of the oven and bake for 15 minutes. After this time, rotate the tins 180 degrees and switch their positions for a more even browning.
Step 15
Bake for an additional 9-11 minutes, until the surface of the cake springs back slightly when touched lightly in the centre and the sides begin to pull away from the tin.
Step 16
Let the cakes cool in the tins for 10 minutes, then carefully release from the tins and allow to cool completely upside down on a wire rack.
Step 17
Meanwhile, make the soured-cream fudge icing. Fill a medium pan to a depth of 5cm of water and bring to a simmer over medium heat.
Step 18
Place 230g butter and 115g finely-chopped chocolate in a heatproof medium bowl and set it over the pan.
Step 19
Turn the heat to low and, stirring occasionally with a spatula, melt until the mixture is completely smooth. (Alternatively, melt the butter and chocolate in the microwave in 30-second increments, stirring until completely smooth.)
Step 20
Whisk 240g icing sugar, 70g sifted cocoa powder and 1 tsp salt into the melted chocolate and butter mixture. Allow to cool to room temperature for 10 minutes.
Step 21
Stir in 320g fridge-cold soured cream and 2 tsp vanilla extract, and whisk vigorously until completely smooth and shiny. (If whisking by hand doesn’t yield a completely smooth, shiny icing, or if you sense that the emulsion is breaking, add a couple of small chips of ice and use a stick blender or food processor to blend the icing until smooth and shiny, about 30 seconds.)
Step 22
Use a serrated knife to even the tops of the cakes if needed.
Step 23
Place one cake on a serving plate, cut-side down, and use a pastry brush to gently wipe away any crumbs.
Step 24
Use an offset spatula to spread about 280g of the icing evenly across the cake.
Step 25
Carefully set the second cake on top, cut-side down – brush away any more crumbs.
Step 26
Put about 140g icing in a small bowl and thin it out with a little water so it’s very easy to spread. Use an offset spatula to spread a thin layer of this thinned icing on the top and sides of the cake, then chill until set, about 15 minutes.
Step 27
Repeat as necessary until no crumbs show through the icing.
Step 28
Use the offset spatula to generously ice the cake with the remaining (unthinned) icing. Begin with the top of the cake, then ice the sides. You may have a little icing left over, but you can eat that straight from the fridge with a spoon in the middle of the night.
Step 29
Decorate the cake with hundreds and thousands or sprinkles if you like.
Step 30
Chill for 30 minutes to set before serving. Wrap and store any leftover iced cake at room temperature for up to three days.