225gRoom Temperature Unsalted Buttera bit extra for buttering the cake pan
4Whole EggsRoom Temperature
250gSelf Raising Flour
Warm up the oven to 180 degrees Celsius (FAN), 350 Fahrenheit FAN, gas 6 or static oven 200 degrees Celsius or 400 Fahrenheit.
Prepare the cake pan
Line the bottom of the cake pan with some baking paper; butter the sides of the tin and then cover with cocoa powder. To remove the excess, bang the sides of the tin and shake the powder out.
Prepare the oranges
You will want different parts of the oranges for this recipe: the zest of half an orange, one tablespoon of fresh orange juice and enough orange roundels to decorate the cake as desired, which should be about 0.2 inch (5mm) thick. Put the slices of orange on the bottom of the cake pan as desired.
Prepare the orange sponge
In the mixing bowl, add the unsalted butter and sugar and mix on low-medium speed, until completely amalgamated and uniform.
Nest, start adding the eggs to the batter, mixing well after adding each one of them for about 30 seconds.
Once all the eggs are well mixed to the wet batter, add the orange zest, baking powder and orange juice and mix well once more (about 15 seconds).
At this stage, add the self-rising flour a bit at a time, mixing in between, to ensure it is mixed well. Once all the flour has been added, the orange cake batter should look creamy and uniform.
Add the batter to the cake pan, trying not to move the decorative orange slices. Once all the batter is in the pan, do not bang it to make it flat, as this will make the air bubbles escape; should the batter not cover all the base of the pan, use a spatula to spread the mixture, without pressing down too much.
Place the cake in the middle shelf of the oven and bake for about 40 minutes, or until the cake is cooked. To check that the cake is cooked, use a toothpick to poke the middle of the cake and if it comes out clean it is ready. When the cake is ready you will also notice that the sponge pulls from the sides of the pan as well.
Once the sponge cake is ready, allow it to completely cool off on a cooling rack before removing it from the pan; once it is cool, remove it from the pan and turn it upside-down, so to have the orange slices on top.
Decorate the cake
To prepare the chocolate drizzle, bring some water to the boil in a sauce pan; you will not need more than 1 inch (2.5 cm) of water. Once it boils, put a heat resistant container (i.e.: glass that can be used in the oven or another pan) on top if it, ensuring the water doesn't come out of the container. Add the dark chocolate to the pan or bowl and melt it, mixing it continuously.
Once the chocolate has melted, remove the container from the heat and decorate the cake. Should you use a spoon to drizzle the cake, you can do so straight away, being careful not to burn yourself; should you prefer to use a sac a poche, then it is recommended to wait for a couple of minutes until the chocolate lightly cools down, but it does not start hardening again.
Once the cake is decorated, allow the chocolate to cool down further and harden, before serving. Enjoy!
It is best to use butter and eggs at room temperature to prepare the sponge cake; it is especially important that the butter is, as this will make the mixing process much easier.