In a large mixing bowl, combine ⅔ cup all-purpose flour and ½ teaspoon salt. Crack 3 large eggs into the bowl. Whisk until the mixture is smooth. Add vanilla and gradually pour in 1 cup milk, whisking continuously, until the batter is smooth and thin enough to pour.
Heat a 12-inch nonstick skillet over medium heat for large crepes. For smaller crepes, use an 8-inch nonstick skillet. Add ½ tablespoon unsalted butter to the skillet and let it melt, coating the surface evenly.
Pour ¼ cup of the batter into the skillet. Immediately tilt the pan in a circular motion to spread the batter into a thin, even layer. Cook for about 1 minute, or until the surface appears dry and the edges begin to lift. Gently flip the crepe with a spatula and cook the other side for about 30 seconds, or until lightly golden.
Transfer the crepe to a plate. Repeat with the remaining batter, adding ½ tablespoon unsalted butter to the skillet before cooking each crepe. This recipe yields approximately 5 large (10-inch) crepes.
