mixture warm but still need it fairly fluid, you have to incorporate it but if it's the least bit hot, it won't work and things start melting and it's so very, very sad so don't do it. Once it's folded in all beautifully, you have completed your mousse! Spread over the ice cream in the crust and then place it back into the freezer for a solid 4 hours. When you are going to serve it, let it stand at room temperature for 10 minutes, but this depends on if you use homemade ice cream or not. My homemade ice cream softens MUCH faster than store-bought. This was in my husband's list of the top desserts that I have made, it is that darn good. So Happy PieDay everyone! Batten down your hatches for that dump of snow we are supposed to get tomorrow. The irony of posting an ice cream pie recipe the day before we get a ton of snow is not lost on me.