For the spaetzle, sieve the flour into a bowl. Add the eggs, egg yolks, mineral water, salt and nutmeg. Beat with a hand mixer until smooth, then beat until the batter starts to bubble. Let the dough rest a little.
Mix the pistachios with oil very finely in a lightning chopper to make a paste.
Press the dough through a spaetzle press into plenty of boiling salted water, bring to the boil, then remove with a slotted spoon and immediately rinse in cold water. Repeat the process until the batter is used up. Drain the spaetzle well in a colander.
Heat the butter in a non-stick pan and fry the spaetzle in it. Finally add the pistachio paste and toss in. Season with salt.
The spaetzle go very well with game dishes or roasts with a lot of sauce.