I always prepare my roasties and parsnips for Christmas early and this is what I do.
Peel the veg and cut them into whatever size you will want to serve them as. Par boil them for about five minutes.
Take them out of the water and place them on a tray with a tea towel under them and leave them to dry and cool.
|parsnips . . .|
|. . . and potatoes (I used King Edwards)|
When cold, dust them in a half and half mix of flour and semolina.
Then space them out on a tray with parchment or easy-leave underneath.
Cover them with cling film and freeze them.
Once frozen, bag them. They will stay separate.
Roast as you would normally do. They come out beautifully crunchy and the spuds are so fluffy.