This recipe is for a classic vanilla cake covered in the best chocolate frosting. This recipe makes a two-layer 22cm diameter cake perfect for small birthday parties or get-togethers.
Preheat the oven to 180°C (350°F) and line 2x 22cm (9 inches) round cake tins with oil and parchment paper.
Add the oil, butter, and sugar to a bowl of a stand mixer fitted with a paddle attachment. Beat on medium-high speed until light and fluffy, about 4 minutes.
Add the eggs to the butter and sugar mixture one at a time. Beat well between each addition and scrape down the sides of the bowl often.
Sift together the salt and self-raising flour then add the flour mixture to the egg and sugar mixture. Beat at low speed until just combined.
Combine the milk and vanilla extract in a jug, and slowly pour this into the cake mixture with the mixer's motor running at low speed. Scrape down the sides of the bowl and mix again, making sure it is lump-free.
Divide the cake batter between the two prepared cake pans and bake in a preheated oven for 40 minutes or until a cake tester inserted into the center of the cake comes out clean. Allow the cakes to cool in their tins for 30 minutes, before turning them onto a wire rack to cool completely.
Chocolate Buttercream Frosting
In a heatproof bowl set over a pan of simmering water, melt the chocolate and butter. Set aside to cool slightly then add the melted chocolate mixture to a bowl of a stand mixer fitted with a whisk attachment.
Add the golden syrup and vanilla extract to the chocolate mixture and mix briefly.
Sift the 400g of icing sugar over the frosting mixture and whisk to combine.
Add the sour cream and beat until the frosting is well combined and homogeneous.
Sift over the remaining icing sugar and add the whipping cream, beat at medium-high speed until the frosting is fluffy. Add the frosting to a piping bag.
Assembly
Use a sharp knife to trim the domed tops of the cake layers if necessary.
Secure the first cake layer onto a cake plate with a bit of frosting. Pipe a layer of frosting over the surface of the cake and smooth this out with a spatula.
Place the second layer of cake onto the first layer with the cut side facing down.
Pipe the frosting over the tops and sides of the cake and use a spatula or cake scraper to even this out. Decorate with sprinkles, serve, and enjoy!