Battenberg Cake (blue?)

Blue Cake? Well I do think blue is rather a weird colour for food - but there again, it is quirky if you like quirky. The recipe is from bbc.co.uk/food and I'm sure it tastes good but I think I might try it without the blue colouring!
Please click the link for the full instructions, but I've just given the sponge cake recipe below:-

Oven: 190 C / 375F - gas 5
8" square cake tin
Ingredients for the cake:
175g (6ozs) softened butter
175g. caster sugar
3 eggs
175g. self-raising flour
1/2 tsp. vanilla extract
(blue food colouring)

Filling:
300g. (10.1/2ozs) icing sugar ]
150g. (5.1/4 ozs.) softened butter ] cream butter & sugar well together till fluffy
6 tbls. strawberry jam

Method:
1. Beat butter and sugar together till light and fluffy.

2. Add the beaten eggs in a little at a time until well combined. Add a spoonful of flour if the mixture looks as if it has curdled. Fold in the rest of the flour - (at this stage add the blue colouring- but only a little otherwise it could look green.)

3. Spoon the batter into your cake tin and level off.

4. Bake for 35 - 40 mins. until firm to the touch and when a skewer is inserted, it will come out clean - - (with no batter sticking to the end!) Remove the cake when done and cool slightly, then place upside down on a wire rack.

For the easy method - split the cake in half and fill, then sift some icing sugar over the top - otherwise click this link to get the full instructions.

For the traditional Battenberg click here.