Step 1
Position a rack in the centre of the oven and preheat oven to 190°C (170°C fan-forced). Spray a 22cm (base measurement) round cake pan with olive oil spray. Line the base with baking paper and spray with olive oil spray.
Step 2
In a medium bowl, whisk the flour and baking powder to combine.
Step 3
In a large bowl, combine the sugar and rosemary. Add the mandarin rind, lemon rind and orange rind, then rub the mixture between your fingertips until it is moist and fragrant. Add the eggs and salt. Using an electric mixer, beat on medium-high speed for about 5 mins or until pale and thick. Beat in the milk. Gradually beat in the oil. Using a wooden spoon, stir in the flour mixture just until blended. Cover and set aside for 10 mins to rest.
Step 4
Arrange mandarin slices and orange slices over the base of the prepared pan. Spread batter over the citrus in the pan. Bake for 30-40 mins or until a toothpick inserted in the centre of the cake comes out with moist crumbs attached. Cool in the pan on a wire rack for 10-15 mins, then invert the cake onto a serving plate.
Step 5
Meanwhile, to make the rosemary whipped cream, in a large bowl, whip the cream, icing sugar and rosemary until thick.
Step 6
Drizzle the cake with a little extra oil. Cut into wedges and serve with the rosemary whipped cream.