They probably buy those chinese pastries (round and similar to momo pastry). It is funny but momo is the easiest fast food to make here (or wherever they have the pastry). It is tedious to make momo in Nepal because of time consuming dough.
 
I used to have a double decker steamer that could steam 100 momo in 30 minutes with just a glass of water. I remember i made about 200 momos once in about 1 1/2 hours. Now we have the Nepal type, which is also time consuming.