Preheat the oven to 180°C and prepare three 15cm diameter cake tins with oil and baking paper.
In a bowl of an electric mixer fitted with a paddle attachment, add the eggs, sugars, and oil. Beat until well combined.
Sift together the flour, salt, and spices.
Add the dry ingredients to the egg mixture and beat until just combined.
Add the grated carrots and walnuts and mix together with a wooden spoon.
Pour the batter into the prepared cake tins and bake in a preheated oven for about 45 minutes or until a skewer inserted into the center of the cake comes out clean. Remove the cakes from the oven.
Allow the cakes to cool in their tins and then remove them from the tins and wrap them in clingfilm and place them in the fridge overnight.
Cream Cheese Frosting
In a bowl of an electric mixer fitted with a whisk attachment add the butter. Beat at high speed until the butter is light and fluffy, and white in color. This can take up to 10 minutes.
Add the icing sugar and beat again.
Change to a paddle attachment and add the cubed cream cheese, beat at a low speed to start with, and once combined beat at a high speed for about 5 minutes. Be sure to scrape down the sides of the bowl as you go.
Once the icing is fluffy, and smooth add it to a piping bag.
Cake Assembly
Remove the plastic wrap from the cakes and place one cake layer on a cake plate. Pipe a layer of frosting on the surface of the cake layer and smooth it out. Continue with all three layers.
Pipe a thin layer of frosting over the surface of the cake, the sides, and the top. Smooth out the frosting with a cake scraper. Place the cake in the fridge to set for a minimum of 1 hour.
Color the remaining frosting with the color of your choice and add it to a piping bag. Remove the cake from the fridge and pipe a layer of frosting over the sides and the top. Smooth the frosting out with a cake scraper. Refrigerate the cake for another hour.
Remove the cake from the fridge and decorate with mini meringues and cake toppers.