In a blender or food processor, combine the flour, milk, eggs, and salt and process for 15 seconds. Turn off the motor. Using a rubber spatula, scrape down the sides of the container. Blend the batter for 20 seconds more, then transfer it to a bowl. Stir in the herbs and let the batter stand at room temperature, covered, for 1 hour. The batter may be made 1 day in advance and kept covered and refrigerated. Lightly oil an 8-inch crepe or saute pan and heat over moderate heat. (Oil the pan each time.) Add 2 tablespoons of the batter and swirl the pan to coat the bottom with the batter. Cook until lightly brown, about 1 minute. Turn the crepe over and cook 30 seconds more. Remove from the pan and place on a square of waxed paper. Top with another square of waxed paper. Repeat until the batter is used, layering sheets of waxed paper between each crepe to prevent sticking. The crepes can be wrapped well in plastic and refrigerated for 2 days or frozen for up to 1 month.