Preheat oven to 450° F.
Grease 10 iron popover pans or individual custard cups very well.
Place pans or cups in oven while it is preheating.
Place eggs, milk, and salt in blender.
Cover and blend at high speed until bubbly.
Add flour and blend at high speed until perfectly smooth.
Remove heated popover pans and fill half full.
Bake at 450° for 15 minutes.
Reduce heat to 350° and bake 15-20 minutes longer.