I am making a White Chocolate ganache covered cake Friday afternoon. The cake will not be eatin until saturday afternoon. Is it okay to leave this cake out uncovered. It does not have perishable filling. I just wasn't sure if the ganache would get really hard or stale. The cake will be a large two tier cake and i dont have box for it.

It should be fine. I've made lots of ganache cakes and had no problems. It will actually remain softer at room temperature than it would in the fridge.

I haven't used white chocolate ganache, but I can't see why it would be any different. It's still just cocoa butter, sugar, and milk solids.

the sturdiness of the ganache depends on the chocolate/cream ratio. with white ganache you will need more chocolate.

I am actually thinking about using the following recipe that I just found, sounds delicious. http://cakecentral.com/recipes/16353/white-chocolate-ganache-buttercream