Preheat the oven to 176℃, lightly grease a 9-inch round cake tin and line the bottom with baking parchment.
Pour the hot milk into a large bowl, swirl in the honey and ground spices, mix in the desiccated coconut, cover and let it steep for an hour.
Sift the flour with salt and baking powder in another bowl.
After an hour, add the beaten egg to the milk mixture, followed by the grated carrots and mix.
Finally, gently fold in the sifted flour till just combined, pour the mixture into the prepared tin and bake for 35-40 min or till a skewer inserted into the cake comes out clean. Turn out the cake onto a wire rack and let cool completely before frosting.
Meanwhile, make the topping by mixing together the cream cheese (softened, at room temperature), icing sugar, vanilla extract and lemon juice until smooth and glossy. Chill in the refrigerator for 30 minutes.
Generously slather and spread the frosting on the cake, sprinkle crushed walnuts all over, and serve.