Combine the milk and eggs in a stand mixer fitted with the paddle attachment on low speed until the egg yolks break up. Add the flour and 1 teaspoon salt and mix on low speed until a thick, pancake-like batter forms. Add the chives, parsley, rosemary and thyme, and mix until well incorporated, 1 to 2 minutes. Transfer the batter to a smaller bowl (to fit more easily in the fridge), cover with plastic wrap and refrigerate for 30 minutes to let the batter rest.
Bring a pot of well-salted water to a boil and have nearby a rimmed baking sheet greased with olive oil. Working over the boiling water and using a rubber spatula, press the batter in batches through the holes of a perforated broiling pan insert, a colander or the large holes of a box grater. The dough will form small dumplings as it drops into the water. Allow the spaetzle to rise to the surface and float for about 30 seconds before transferring it to the baking sheet and continue cooking the rest of the batter. (If you are not using the cooked spaetzle right away, toss it with a little olive oil and refrigerate, covered in plastic wrap, for up to 2 days.)
Reheat the spaetzle by following the directions in the recipe calling for it. Or, for a delicious side dish, heat a large saute pan over medium-high heat and add 2 tablespoons olive oil and the butter. When the butter is melted, add the spaetzle and cook, tossing occasionally, until golden brown, about 2 minutes. Season to taste. Sprinkle with Parmesan, if using, and serve.