Place the riced potatoes into a large bowl. Add in 1 cup potato starch, both eggs, salt, pepper and nutmeg to make a dough that holds together when formed into dumplings. If the mixture is too moist, add a bit more starch. If for some reason it ends up being too stiff, crumbly and dry, you can add a little milk till softened.
Now flatten the dough in the bowl and divide it into four equal quadrants. You should be able to get about 3 dumplings from each section. Have a bowl of water next to you to wet your hands between each dumpling. Take the amount for one in your palm and roll it into a ball. Now flatten it slightly and add about 4 bread croutons into the centre. Fold the dumpling dough around them and then roll to smooth out the ball. It should be around 2 inches in diameter. Place this onto a wax paper lined baking sheet. Repeat with remaining dough.
As long as they are not touching, they can be covered with plastic wrap or a bag, sealed and stored in the fridge, or cold cellar if you want to prepare them in advance before cooking the next day.
Try to choose potatoes that are of similar size so that they will cook evenly. I usually choose ones that are between small and medium in size just to ensure that they cook through with ease.
I like Yukon Gold, for their versatility, and the lovely golden hue they add to the final dish. But Russet potatoes will also work fine.
If you can't find potato starch, you may use cornstarch. But I do think potato starch will guarantee the best flavour.