Heat oven to 180C/160C fan/gas 4 and line a 12-hole muffin tin with cases.
In a large mixing bowl, mix the dry ingredients and orange zest.
Whisk together the eggs and oil, then stir into the dry ingredients with the grated carrot.
Divide the mixture between cases and bake for 20 mins until a knife poked in comes out clean.
Meanwhile, put butter, sugar and small Chantenay carrots in a small pan and cook for 10 mins. Spoon onto a cooling rack and allow to cool
For the icing, beat the butter together with the cream cheese, icing sugar and vanilla.
When the cakes are cool, swirl the icing on top of the cakes, and then place the candied Chantenay carrots on top with a mint leaf.