To achieve the lightest, fluffiest popovers, the eggs and milk should at least be room temperature. Some recipes call for some of the milk or even cream to be heated to about 100 degree F and whisked in at the last minute.
I didn’t heat the milk but I did let the batter rest for about an hour so that the flour was fully hydrated. I also set the bowl on the back of the stove, over the oven vent, while it was pre-heating.
1 1/2 cups (6.75 oz) all-purpose flour
1 1/2 cups (12 oz) whole milk, room temperature
4 large eggs, room temperature
3 tablespoons unsalted butter, divided
3/4 teaspoons kosher salt
If the eggs and milk are cold, before combining them, submerge the whole eggs in hot water for about 10 minutes. Melt 1 1/2 tablespoons of butter and allow to cool.
In a medium bowl measure or weigh out the flour and whisk in the salt. Set aside. In a large bowl whisk together the warmed eggs and room temperature milk until very frothy and displaying visible air bubbles. This should take about 1 minute.
Add flour and salt to egg mixture and whisk until batter is the consistency of heavy cream with some small lumps remaining. Whisk in the cooled melted butter. Set the batter aside for about 45 minutes.
When ready to bake off, set a rack on the lowest level of the oven and if you have a pizza stone set it on top of the rack. Pre-heat the oven to 450 degrees giving it a full 15 minutes to get really hot. Set the popover pan on a sheet pan and place it in the oven for about 3 minutes.
Remove the pan from the oven and generously spray with non-stick cooking spray. Divide the remaining 1 ½ tablespoons of butter evenly between the 6 popover cups. Using a silicone brush, quickly brush the butter up the sides of each cup.
Give the batter one more quick whisk and fill popover cups about three-quarters full with batter. Bake for 15 minutes, then reduce oven temperature to 375 degrees F. Continue baking until golden brown, about 25 minutes more, give or take. DON’T OPEN THE OVEN DOOR!
Popovers lose their crunch quickly if left in the pan, so turn them out on a wire rack immediately and poke a small opening in the side of each with a paring knife to let the steam escape. Serve right away.