2 tablespoons unsalted butter, melted, plus more for pan
1 1/2 cups whole milk, plus more as needed
1 1/2 cups (195 grams) all-purpose flour
1 teaspoon sugar
1 teaspoon kosher salt
In a medium bowl, whisk together the eggs until well blended. Add the butter and milk to the eggs, and whisk to combine.
Whisk the flour, sugar, and salt into the egg mixture until well combined. Don’t worry if there are a few small lumps. Let the mixture sit for about 30 minutes (or it can be made a day ahead). All the lumps will dissolve as it is sitting. Once the batter has sat, check it to make sure it is thin enough. It should resemble maple syrup. If not, add extra milk until it does.
Heat a well-seasoned crepe pan over medium heat. Add a small pat of butter to the pan and then wipe it off, leaving just the butter residue.
Ladle a small amount of batter into the pan, just enough to thinly coat the bottom when you swirl it around; the amount will depend on the size of your crepe pan. The batter should be thin and lacy around the edges.
Allow to cook until the crepe is golden brown on the bottom and appears dry on top, 1 to 2 minutes.
Flip it over and cook for another 30 to 60 seconds. Repeat with the rest of the batter, adding more butter each time.
If not using immediately, stack crepes on a plate, wrap in plastic wrap, and refrigerate up to 3 days.