Preheat oven to 160*c Fan Oven/180*c/350*f/Gas Mark 4.

Grease and line a square baking tin with baking paper.

Place the self raising flour, margarine, eggs, milk and vanilla paste into an electric mixer, and beat together until light and fluffy, and spoon in the mixture into your prepared tin.

Cook for 45 minutes to an hour checking regularly, or until light and fluffy. You can tell it's ready when it springs back when lightly pressed. You could also insert a skewer into the middle of the cake and if it comes out clean, then the cake is ready.

Once ready, remove from the oven.

Allow it to sit in the pan for roughly 10 minutes before turning out onto a wired baking tray and allowing it to cool completely.

Once cooled, using a sharp knife, 'trim' any excess cake to create a flat surface, discarding any extras.

Turn the cake over, so that the bottom has now become the top, and remove the baking paper.

Whilst the cake is cooling, make the icing. Add icing sugar to a cup/bowl and add a small amount of water and mix. If the texture is too thick, then add a little bit more water. If it’s too thin add a little bit more icing sugar. Keep going until you reach your desired consistency. I like mine to be quite thick so that I have a nice thick layer of icing on top of my cake.

Add the food colouring a little at a time until you reach your desired colour.

Spread/pour a layer of icing on to the cake and allow it to set.

If you want to add any additional toppings, such as sprinkles, now is the time, before the icing sets completely.

Using a sharp knife, cut the cake into squares, this can be smaller, more dainty bites, or larger and heartier slabs, it's completely up to you!