1. Prep for your experiment by lightly greasing 12 muffin cups and the top of the pan, as the popovers will rise and overflow a bit.
2. Whisk the eggs in a 4 cup measuring cup until frothy, then whisk in the milk. Sift the flour and salt into the liquid. Whisk until the batter is smooth and lump free, about 30 seconds. Whisk in the butter and let the batter rest for 15 minutes.
3. Place the oven rack in the center position and heat the oven to 425 degrees F. When the oven is heated, whisk the batter again until smooth. Pour the batter into the cups, dividing it equally (the cups will be about half full, leaving room for the hot air bubble in each to form and rise).
4. Bake the popovers for 15 minutes, then reduce the heat to 375 degrees F (350 degrees F if you re using a dark pan), and bake for 10 minutes more. Do not open the oven before 25 minutes have elapsed or the bubbles could collapse.
5. Remove the pan from the oven and use a knife to poke a small hole into the top of each popover so that the steam can escape. Let the popovers cool in the pan for a minute or two, then remove. Wait another minute or so, then carefully tear open the popovers to eat, avoiding any steam.