In val Senales sulla neve
Beautiful as well as challenging all-snow trail, to be done as usual about a week after the last snowfall so that the snow is well groomed by vehicles and snowshoers.
I recommend doing the trail from Maso Corto to Berglalm by 9:30 max 10 a.m., because after that it is very busy with hikers and you can hardly move around by bike.
You park at Maso Corto (free in winter) and go up the toboggan run to Lazaun (but you can also start towards Berglalm, actually better). At Lazaun you turn onto the beaten winter trail or cross-country track if the snow is hard.
You go down the same path to Maso Corto and up to Berglalm. This is a narrow, snowshoe-beaten trail, but if the snow is well groomed it is completely rideable on an ebike and with about 15 minutes pushing on a fatbike.
Of course you have to know how to ride on the narrow snowy trails, always staying in the middle of the trail. At Berglalm refreshment (always open) and then very challenging, very steep but beautiful descent on snow to Gerstgras. From here back to Maso Corto on winter trail always beaten uphill.