Soft Carrot Cake Sponge topped with Buttercream

INGREDIENTS: Egg, Sugar, Carrots, Orange, Bicarbonate of Soda, Ginger, Cinnamon, WHEAT Self raising Flour [WHEAT Flour, Calcium Carbonate, Iron, Niacin, Thiamin], Raising Agents [Calcium Phosphates, Sodium Carbonates], Sunflower oil, Vegetable Fat Spread 70% [Vegetable Oils (Rapeseed, Palm, Palm Kemel), Water, 1.2% Salt, Emulsifier: Mono- and Diglycerides of Fatty Acids; Acidity Regulator: Citric Acid; Flavouring, Colour: Carotenes; Vitamin A, Vitamin D], Icing Sugar [97% Sugar, Maize Starch]