Place 6 cavity popover pan in your oven. Preheat oven to 450º F and allow pan to get hot and oven to fully preheat.
In a high speed blender or food processor, add milk and eggs and blend on low for about 30 seconds. Add flour and salt and continue to blend batter on low until all ingredients are uniformly combined, about 45-60 seconds. Allow the batter to rest at room temperature for 20-30 minutes (longer okay) in order for the batter to rest and hydrate.
Remove popover pan from oven (it will be extremely hot) and add a small 1/2 tsp pat of butter into each of the 6 cavities of your popover pan and allow it to melt in the hot pan. Evenly distribute the batter in each cavity (you'll have enough to fill each cavity to the near top).
Place pan on a baking sheet and then into the oven and bake for 20 minutes at 450º F, then reduce heat to 350º F and bake 10 minutes longer.
Poke a small hole (using a butter knife) into the top of each popover to allow the steam to escape, then remove the popovers immediately from the popover pan and onto a wire rack to cool. Do not leave them in the pan to cool or the steam will make the bottoms soggy. Serve immediately (popovers are best served warm).
Store leftover popovers in a zip top bag for 1-2 days. You can use a muffin pan and make 12 muffin-popovers. A muffin pan has a wider cavity and therefore will not allow for a dramatic rise. Always bake popovers on top of a baking tray to avoid a huge mess in your oven. See full post for more tips on how to bake popovers in your muffin pan or inside ramekins.A lot of people struggle to get their popovers to rise. Here are some reasons why they didn't rise:-Did you use a proper popover pan? If you are going to make popovers several times a year, it's worth investing in a proper pan.-Make sure your pan is hot before you add the batter. When the batter hits the hot pan, steam will form right away and will help begin the leavening process of the popovers.-Do not open the oven while they bake. This will impact the steam pockets inside the popovers.