To make the cake, pour the bourbon into a small saucepan and add the sultanas. Heat gently, without allowing the liquid to come to the boil, for 5 minutes. Set aside to cool.
Preheat the oven to 200ºC/180ºC fan/Gas Mark 6. Line the bases of 2 x 20-cm (8-inch) round cake tins with non-stick baking paper.
Sift the flour, baking powder and cinnamon into a large mixing bowl. Mix in the salt, sugar, carrots, nuts and roughly two-thirds of the orange zest (reserve the rest for the icing). Add the oil, eggs and soaked sultanas, along with any bourbon left in the pan, and mix thoroughly.
Divide the mixture equally between the prepared cake tins and gently smooththe surfaces. Bake for 25–30 minutes, until risen and a skewer inserted in the centre of each cake comes out clean. Leave to cool in the tins for 5 minutes, then turn out the cakes onto a wire rack and leave to cool completely.
For the icing, put the butter and icing sugar into a mixing bowl and use a hand-held electric beater to beat them together until smooth. Now gradually whisk in the bourbon. Add the cream cheese and reserved orange zest and whisk until smooth.
When the cakes are completely cold, place one cake layer on a cake board or serving plate and top with half the icing. Level out the icing until it is spread evenly across the surface of the cake. Align the second cake layer on top, then top with the remaining icing, again, smoothing it out to an even thickness.
Chop the pecan nuts and scatter over the cake to finish.