Leftover Rampage, Gnocchi

Sadly, the vegetables from Christmas have gone past the point of revival (had there been enough and it was okay to eat I would have made a frittata, but that can be for next year), but the huge pile of mashed potatoes are still fine to use, and at first I considered potato bread or scones, but gnocchi is one of my favourite flavour absorbing carbohydrates and I've been waiting for some leftover mashed potatoes to make them with.
Again, using the leftover mash in gnocchi, especially with the essential '00' flour (you CANNOT use regular plain flour) is probably much less superscrimper than throwing it away, but there's so much charm in making a meal out of one that was so spectacular previously, and making your own pasta induces plenty of obnoxiously satisfying smugness that I can relish in.
Gnocchi are rather too stodgy straight from the water, so make sure you have a good sauce for them or like I do, finish in butter and parmesan. So just a small, light side.
1)You should think in ratios rather than weight here, as it depends on how much mash you have. All you need to know is it's 1 part '00' flour to 2 parts mashed potato to 2 tsp salt. If the potatoes are very crumbly and dry you can add an egg, but it shouldn't be necessary. Dump the flour on the table and pile the mash and salt on top, and gradually start incorporating the flour into the mash. It takes a while and is quite messy, but they'll eventually come together to a soft ball of dough. Add a little more flour if it's too sticky, but you shouldn't have to. You want them more potatoey than floury.
2)You don't have to leave it to rest like regular pasta, just divide it into four and roll each one into a thin log, and divide into balls smaller than what you might think, as they do expand a lot in the water. Keep everything floured as they can stick together.
3)When you have a pile of dough balls, you need to add surface area to them. You can do this by pressing a thumb in the centre, or the more common method of rolling them down a fork. Do this by holding the fork upside down, pressing the dough ball into it with your middle finger, and then rolling it down over itself with your thumb. It takes a while and some practice, but they don't need to be perfect as the pattern blurs a lot in the water.
4)In a large pan of well salted water, drop the gnocchi in and do yourself a favour by doing them in batches. When they rise to the surface they're ready, and finish them off by crisping them in butter and shaving over parmesan.1