Preheat the oven to gas mark 4/350of/180oc and line two 23cm/9-inch cake tins with baking paper. Begin by grating the carrots and setting aside. In a bowl whisk together the dry ingredients (self-raising flour, bicarbonate soda, cinnamon, ginger, nutmeg and salt).
Whisk together the vegetable oil, eggs, sour cream, vanilla extract, amaretto, brown sugar and golden granulated sugar until well combined then add the grated carrots and continue to beat until the carrots are well incorporated. Pour the dry ingredients into the wet ingredients and continue to beat until all the ingredients are well combined and ensuring not to over mix.
Distribute the cake batter equally between the 2 baking tins. Bake for 45 minutes or until a cake tester inserted into the middle comes out clean. Remove from the oven and place the tins on a wire rack and allow to cool in the pan for 20 minutes. Remove the cakes from the tins and place on a wire rack to completely cool.
Once the cakes have cooled, use a stand mixer or handheld mixer to beat or whisk the butter until creamy and fluffy, add the cream cheese and continue to beat, slowly incorporate the icing sugar until it has all combined and set aside.
If needed, level cakes then place one of the cakes on a turntable or cake stand. Spread some frosting on top and spread out equally using a palette knife. Lay the second cake on top and spread the rest of the frosting on and around the whole cake. Decorate with chopped pecans.