Set your oven to 450°F right away.
This high heat is crucial for popovers.
Let it heat for at least 15 minutes.
Grease your popover pan with butter generously.
Crack eggs into your mixing bowl.
Add the milk and whisk together well.
Pour in the flour and salt gradually.
Whisk until the batter is smooth.
Add melted butter and mix again.
Some small lumps are totally fine.
Pour batter into each cup halfway full.
Don't fill them to the top.
Leave room for the popovers to rise.
They'll puff up a lot during baking.
Put the pan in the hot oven.
Bake for 20 minutes at 450°F.
Then reduce heat to 350°F without opening.
Bake for 15 more minutes until golden.
Don't open the oven door at all.
This keeps them from collapsing.
Remove popovers from the oven carefully.
Poke each one with a knife tip.
This releases steam and keeps them crispy.
Serve them right away while they're hot.