I am going to attempt to cover a cake with white chocolate, to use under fondant. I haven't made ganache with white chocolate before. I have read to use a 3 to 1 ratio chocolate to cream. Do you whip it?

I use chocolate ganache 50% 50% ratio, whipped for my chocolate filling. I'm not sure if that's right for covering a cake though.

Any advice is appreciated!

Thanks!

Yes it's 3/1 ratio for white chocolate ganache. When covering a cake with dark chocolate ganache I use 2/1 ratio. 12 ounces of semi-sweet chocolate to 1 cup heavy cream. I don't whip it though, just spread on my cake as is. I make it 24 hours before needed so that it has time to thicken before using.