Wrap the potatoes in foil and bake at 350 until they can be easily pierced with a knife, about 30-45 minutes depending on size. Remove the potatoes from the oven and cool completely.
The potatoes can be riced the next day after chilling in the fridge as well. Skin the potatoes with a paring knife, Then cut into pieces and press through a ricer.
If you have a circular rotating ricer, work in small batches to avoid making the potatoes gummy. Put the riced potatoes on a bowl, add the salt, numeg, and egg yolk and mix until combined, then add the flour and mix (don’t knead) until an even dough is formed.
Transfer the dough to a cutting board, cover with a towel and allow to rest for 5 minutes before rolling out. Roll the dough into logs about 1 inch in diameter, then cut using a bench knife and roll off a fork or gnocchi board if desired.
As you cut the gnocchi, toss them lightly in flour and either boil fresh, toss with oil and reserve for dinner, or freeze, lightly floured on cookie sheets, transferring to freezer or vacuum bags for cooking straight from the freezer.