In a bowl, whisk together the flour, eggs, milk, and salt. Stir until the batter is well combined and develops bubbles. You can also use a mixer. Let the batter sit for 5-10 min.
Put a colander into a bowl to drain the spaetzle once cooked and bring a large pot of water over high heat to a boil, add about 1 tbsp of salt to the water, and reduce the temperature to a simmer.
Using a spaetzle-maker or a large-holed sieve, press the spaetzle batter through to form individual pasta noodles.
From this point it's best to work in batches. Once you've used about 1/3 of the batter, allow the spaetzle to cook for about 2-3 minutes, or until they float to the top.
Using a slotted spoon, take them out of the pan into the colander to drain.
Now you can serve the spaetzle immediately, but they taste great sautéed in some melted butter for a more crispy texture. (If you don't plan to serve them straight away, make sure to mix the hot spaetzle with about 2 tablespoons of butter so they don't stick together.