Step 1
Heat your oven to 160C fan-forced (180C conventional). Line a 1.2-litre loaf tin. Whisk together the sugar, oil, eggs, yoghurt and vanilla, then add the flour, baking powder and salt and mix to combine. Pour into the loaf tin and bake for 1 hour, or until a skewer inserted into the cake comes out clean.
Step 2
While the cake is baking, make the syrup. Peel the citrus with a peeler, cut any white pith from the zest and finely julienne the zest of the lime, one of the lemons, and half of one orange. Juice all the fruit and combine them – you should have about ¾ of a cup. Mix the juices and sugar and bring to a simmer in a saucepan for about 2 minutes, then stir through the zest. Allow to cool.
Step 3
When the cake comes out of the oven, poke holes all over the top with a skewer. Slowly pour the syrup and zest over the cake and allow it to soak in. Once the cake has cooled, slice and serve with sour cream.
