This is the cake I made last Saturday.
1 cup unsalted butter
1 heaping cup superfine sugar
scant 1/2 cup plain yoghurt
2 lemons, zested and juiced
2 limes, zested and juiced
2 oranges, zested and juiced
2 cups self raising flour
1 cup sugar
whipped cream to serve
Preheat oven to 350 deg F and grease and line 91/2 inch springform pan with parchment paper. Cream the butter and sugar then fold in the eggs, yoghurt and citrus zest. Sift in the flour and fold it through the batter. Spoon the batter into the prepared pan. Bake for 45 minutes or until golden brown and a skewer comes out clean.
Meanwhile put the citrus juice in a saucepan with the sugar, bring to the boil and stir until sugar dissolves. Remove from the heat.
When the cake is cooked prick it all over with a skewer and pour half the syrup over it. Keep the rest for serving. Allow to cool. Serve with reserved syrup and cream.
This is (obviously) an American recipe. I made no allowances and just used metric measures. I also used wholemeal flour without changes because that was what I had. I used 3 limes instead of two because they looked too little, and I used double cream instead of whipped. Oh, and I didn't have a springform pan, it comes out of a normal one ok.