Cream 175g butter for about 7 minutes until it is creamy and fluffy and nearly white. Then beat in 300g icing sugar for about 3 minutes and then 1 tsp vanilla extract and then add in about 175ml double of double cream and beat for another 5 minutes. You can play around with the amount of cream- the less you add the stiffer it will be- the more you add the fluffier.
This is the result- very nice for piping or spreading on cakes.
I used it on some Easter cupcakes.