Lightly spoon flour into a dry measuring cup, level with knife. In a medium bowl combine measured flour and salt, stirring with a whisk. Set aside.
Combine milk and eggs in a medium bowl, stirring with a whisk until blended, let stand for 30 minutes. Gradually add flour mixture, stirring well with a whisk. Stir in melted butter.
Place a 6 cup standard popover pan in the oven for 5 minutes. (Alternately, you can use a 12-cup muffin pan and make 10 mini popovers).