Preheat the oven to 180°C (160°C for fan assisted ovens), Gas Mark 4. Lightly grease 2 x 20cm (8-inch) round pans and line the bases with baking paper.
Open the cake box, remove enclosed frosting sachet and reserve for another use. In a medium bowl, mix the coconut and carrots with 3 tablespoons of the dry cake mixture. Set aside.
Tip the remaining cake mix into a large mixing bowl and stir in the spices. Add the oil, water and eggs and beat with an electric mixer on a low speed for 30 seconds, then on medium speed for about 2 minutes.
Using a metal spoon, fold in the coconut and carrot mixture followed by the mandarin segments. Divide between the prepared pans and gently level the surface.
Bake for 25-30 minutes until risen and golden and a skewer inserted into the center of each cake comes out clean. Cool in the pans for 5 minutes then turn out onto a wire rack and leave to cool completely.
Spread half the cream cheese frosting over the top of one cold cake. Place the second cake on top and spread over the rest of the frosting, swirling it with a small palette knife. Scatter over the chopped pecan halves. Slice into 12 to serve.