Position a rack in the lower third of the oven; preheat to 450 degrees . Grease a standard popover pan. Using a blender, mix the eggs, milk, flour and salt at low speed until just combined, about 20 seconds. Add the melted butter; blend for 10 seconds.
Pour about 1/3 cup of the batter into each prepared cup (filling about halfway). Bake for 20 minutes. Lower the oven temperature to 350 degrees . Bake until puffed, golden and crisp, 15 to 20 minutes. Using a small, sharp knife, carefully cut around the sides of each popover to release. Serve immediately.