Use a little of the olive oil to grease a 24cm cake tin and line the bottom with greaseproof paper. Preheat the oven to 180˚C/gas 4.
Put the sugar, eggs, salt and vanilla extract into a large mixing bowl and beat until pale and fluffy. Using a wooden spoon, slowly stir in the olive oil, milk, lemon juice and orange juice. Add the two zests. In a separate bowl, mix the baking powder into the flour, and when combined, fold into the olive oil mixture until smooth.
Pour the cake mix into the greased tin and place in the oven for about 45 minutes, until the top feels springy, a skewer comes out clean when inserted into the middle, and the cake is golden brown.
Cool on a wire rack and serve warm, generous slices with a sweet wine, or enjoy cold the next day with coffee.24cm cake tin