Preheat the waffle iron. Combine the flour, salt, baking powder, and sugar in a medium-size mixing bowl. Add the milk and the eggs. Whisk to combine. Pour the melted butter and the vanilla into the batter and whisk until mostly smooth.
Pour onto the hot waffle iron and cook according to manufacturer’s directions. Serve warm or let cool completely.
FREEZER NOTE: Freeze completely cooled waffles in zipclose bags. Reheat from frozen in the toaster or microwave.