Is it pistachio nut cream in a jar, from Sicily? If so, you can use it to fill a cannoli. Just mix the cream with a nice smooth ricotta cheese and (since some folks aren't too fussed on candied fruit) mini-chocolate chips. Gorgeous taste.
I don't have a pastry bag, so I use a ziploc bag for filling the cannoli shells; fill the bag with the ricotta mixture and then snip off just enough from the tip end of the ziploc bag and squeeze it into the cannoli shell. Once filled, you can dip the ends of the cannoli into chopped nuts.
I've found that the ready-made cannoli shells work fine and save you quite a bit of time.