For the Sour Cream Chocolate Cake

Make sure all of the ingredients are at room temperature before starting.

1. Preheat the oven to 180°C/350°F (without fan).
2. Line the bottom of 2 x 20cm/8 inch round cake pans with baking paper and grease the sides with butter.
3. Place all of the ingredients into the bowl of a food processor and blitz until the mixture is well-combined. The batter should be thick and smooth.

Alternatively, if you do not have a food processor:

1. Cream the butter and sugar in the bowl of a stand mixer with the flat paddle attachment.
2. Slowly beat in the flour, cocoa, sugar, baking powder, baking soda and salt.
3. Beat on low speed until all of the ingredients are incorporated.
4. In a small bowl or jug, lightly whisk together the sour cream, eggs and vanilla.
5. Slowly add the wet ingredients to the mixer, and beat until the batter is thoroughly mixed.

To Bake the Chocolate Cake

1. Pour the batter evenly into both prepared cake pans. I generally find that the weighed batter for each cake is approximately 430 g.
2. Bake for 25-30 minutes, or until a skewer inserted in the middle comes out clean.
3. Place the cake pans on a wire rack and let the cakes cool in the pan for about 10 minutes, before removing them to a wire rack to cool completely. I like to cool the cakes with the bottom facing up, so that the top of the cakes can flatten as they cool.
4. I often make the cakes the night before serving and leave them to cool overnight.

For the Sour Cream Chocolate Frosting

1. Melt the chocolate and butter in a bain-marie or a bowl over a pan of simmering water, taking care not to let the bowl come into contact with the water. If you have an induction stove, you can melt the chocolate and butter directly in a saucepan over low heat.
2. Once the chocolate has melted, take the bowl off the heat and let it cool slightly.
3. Stir in the sour cream, vanilla extract and golden syrup.
4. Measure the icing sugar (powdered sugar) into the bowl of an electric stand mixer.
5. Using the flat paddle attachment, slowly beat the chocolate mixture into the icing sugar (powdered sugar).
6. Beat on medium speed until all of the ingredients are well incorporated.
7. The frosting should be thick enough to cover the cake, but soft enough to spread easily.

To Assemble the Cake

1. Cut four thick strips of baking paper and place them on a large plate or cake stand in the shape of a square. The baking paper is to help keep the serving plate clean while you are frosting the cake.
2. Place one cake on top of the baking paper.
3. Spread about 1/3 of the frosting over the cake in a thick layer.
4. Place the second cake on top and spread another 1/3 of frosting over the cake.
5. Use the remaining frosting to cover the sides of the cake.
6. Once you have finished frosting the cake, carefully remove the pieces of baking paper.
7. Leave the cake to set for at least 1 hour before serving.