- 280 g Margarine (at room temperature) - 280 g Caster Sugar (Superfine Sugar) - 5 Free-range Eggs (at room temperature) - 280 g Self-raising Flour - 350 g Icing Sugar (Powdered Sugar) - 3-4 tbsp Boiling Water - Sprinkles [to decorate] (optional) 1# Pre-heat your oven to 180°c (160°c for fan assisted oven, Gas Mark 4 or 350°F) and a 9×12 inch baking tin with greaseproof paper. Set aside. 2# In a large bowl, cream together the margarine and sugar until light and fluffy. 3# Add the eggs one at time, ensuring each is mixed through before adding the next. 4# Sift in the flour and gently fold to create a batter (I add lemon essence at this stage). 5# Transfer the batter to your pre-lined tin and bake in your pre-heated oven for 30-40 minutes until risen, golden and a skewer inserted comes out clean. 6# Leave to cool in the tin for a few minutes before transferring to a wire rack to cool completely. 7# Once your cake has cooled completely; in a bowl, mix the icing sugar with a few teaspoons of boiling water, adding a little water at time until you have a thick pouring consistency. Pour the icing onto your cake, using a spoon to guide it to the edges. Finish with some rainbow sprinkles. https://bakingwithgranny.co.uk