Preheat oven to 425°F

generously grease aluminum popover pans withsoftened butter.

You'll need a pan to make 12 popovers.

Place pan in oven for exactly 1 minute to melt butter.

Whisk together the flour, salt, eggs, milk, and melted butter until smooth.

The batter will be thin. Fill the popover pans less than half full and bake for exactly 30 minutes. Do not peek.