Preheat the oven to 160°C and grease a 22cm round springform cake tin and line the base with baking paper.
Sift the flour and spices into a large bowl then stir in the brown sugar and grated carrot. In another bowl, whisk together the eggs, oil and sour cream and then add into the carrot mixture and stir until well combined. Spoon the mixture into the prepared cake tin and bake for 1 hr and 10 mins or until a skewer comes out clean when inserted into the middle. Leave to stand in the tin for 10 mins before turning out onto a rack.
For the icing, beat the cream cheese, butter, zest and juice until light and fluffy, gradually adding the icing sugar. Spread over the cooled cake.