Preheat your oven to 450-degrees. In a large measuring cup whisk together the flour and the salt.
In a small bowl whisk the eggs until light and fluffy, about 30 seconds. Add the milk and the 1 tablespoon melted butter, blending into the eggs.
Add the milk and egg mixture to the flour and whisk until well blended, about 30 seconds. Make certain all the flour is mixed into the batter – it should be smooth and will be somewhat thin. Set the batter aside to rest for about 2 to 3 minutes while you prep the pan.
Heat a 6-cup popover pan in a 450-degree oven for 2 minutes. Then remove the pan and spray the bottom and sides making sure to coat each cup really well – don’t skip this step or the popovers will stick to the pan. Divide the remaining 1-½ tablespoons of butter into the bottom of each cup, about ¼ teaspoon butter per cup.
Pour the batter into the cups, dividing between each – they should be about two-thirds full.
Bake the popovers on the second from lowest rack in a 450-degrees for 20 minutes then reduce the heat to 350-degrees and bake for an additional 12 minutes. Do not open the oven before the baking time is up.
When the popovers are done, using the tip of a sharp knife, poke a small hole in the top or side of each popover. This will allow the steam to escape and keep the inside of the popovers from becoming soggy.
Remove the popovers from the pan and place on a wire rack to cool. Use a sharp knife to loosen the sides if necessary. Serve hot or room temperature.