Yes! You can whip creme fraiche (homemade or store-bought) and mascarpone in exactly the same way as you whip cream. With mascarpone, you want to get it to room temperature and then whisk it fairly gently as it will get grainy if you over-whisk. You can also whip mascarpone and cream (or creme fraiche) together in the same bowl at the same time. NOTE: creme fraiche and mascarpone both will start out very thick, thin out once you start whisking, and then thicken back up pretty quickly as you whip air into them.