In a large bowl, combine flour, salt, pepper, and nutmeg.
Whisk eggs and milk together in a medium bowl. Gradually whisk milk mixture into flour, whisking until smooth. Let sit for 15 to 30 minutes.
Poke about 40 1/4-inch holes in the aluminum pan using a paring knife.
Bring 4 quarts of water to boil in a Dutch oven and add 1 tablespoon salt. Set the aluminum pan on top of the Dutch oven. (You may want to turn the heat down a touch and work quickly as the aluminum will get hot quickly.)
Pour about half the batter into the aluminum pan. (Note: you might want to do a test with a small amount of batter to make sure your holes are big enough.)
Use a rubber spatula to press the batter back and forth across the holes. Set pan aside.
Boil until spaetzle float, about 1 minute. Remove them with a slotted spoon and place on a paper towel-lined plate. Repeat with remaining batter.
Heat the oil in a large nonstick skillet. Add shallot and cook for 1 minute. Add spaetzle and cook for 5 to 7 minutes, stirring occasionally.
Remove from heat and stir in butter. Check for seasoning and add more salt and pepper if desired.