1. Preheat the oven to 180°C (160°C Fan, Gas Mark 4). Lightly spray 3 x 18cm (7inch) round Victoria sponge tins with Cake Release Spray. In a mixing bowl, beat half of the white vegetable fat with half of the sugar until creamy in texture.
2. Gradually whisk in 2 eggs and 1.25g (¼ tsp) salt. Sift half the flour and 10g (2 tsp) Baking Powder on top. Using a large metal spoon, fold in the dry ingredients. Stir in half the milk to soften the mixture to make a soft dropping consistency.
3. Divide the mixture equally between 3 bowls. Choose 3 different Gel Food Colours and mix in sufficient drops of one colour into each batch of mixture to form a vibrant shade.
4. Spoon the mixture into the cake tins, smooth the tops and bake in the oven for about 15 minutes until lightly golden and just firm to the touch. Leave to cool for 5 minutes then turn on to wire racks to cool.
5. Using the remaining ingredients, repeat the cake making as in steps 1 and 2, and colour with the remaining 3 colours. Bake and cool as above.
6. To decorate, put the butter in a bowl and beat until smooth and glossy. Gradually sift and beat in the icing sugar until creamy and soft and add the Sicilian Lemon Extract.
7. Put 450g (1lb) icing aside, and spread the remaining icing lightly over 5 of the cake layers. On a serving plate, stack the layers on top of each other as illustrated.
8. Spread the remaining icing over the top and sides of the whole cake to serve. Slice and enjoy!