Preheat oven to 450°F (230°C). Place 6 popover cups or a 6-cup muffin tin into the oven to heat.

In a mixing bowl, whisk together flour and salt.

In a separate bowl, whisk eggs and milk until well combined.

Pour wet ingredients into dry ingredients and whisk until smooth with no lumps. Stir in melted butter.

Carefully remove hot tin from oven and lightly brush each cup with melted butter.

Divide batter evenly among cups, filling about two-thirds full.

Quickly return tins to the oven. Bake at 450°F for 15 minutes without opening the oven door.

After 15 minutes, reduce oven temperature to 350°F (175°C) and bake 10–12 minutes more until deeply golden and puffed.

Remove from oven, immediately pop out the popovers, and serve warm. They will deflate slightly but remain hollow for filling.