? 1. Adjust oven rack to lower-middle position and heat oven to 450 degrees. Grease interior of 6-cup popover pan with shortening, then dust lightly with flour. Whisk eggs until light and foamy in medium bowl. Slowly whisk in milk and butter until incorporated.

? 2. Combine flour, salt, and sugar in large bowl. Whisk three-quarters of milk mixture into flour mixture until no lumps remain, then whisk in remaining milk mixture. Transfer batter to large measuring cup, cover with plastic, and let rest at room temperature for 1 hour. (Alternatively, batter can be refrigerated for 1 day. Bring to room temperature before proceeding with recipe.)

? 3. Whisk batter to recombine, then pour into prepared popover pan (batter will not quite reach top of cups). Bake until just beginning to brown, about 20 minutes. Without opening oven door, decrease oven temperature to 300 degrees and continue to bake until popovers are golden brown all over, 35 to 40 minutes longer. Poke small hole in top of each popover with skewer and continue to bake until deep golden brown, about 10 minutes longer. Transfer popover pan to wire rack. Poke again with skewer and let cool 2 minutes. Turn out popovers. Serve.

? Make Ahead: Once popovers have cooled completely, they can be stored at room temperature in zipper-lock bag for 2 days. To serve, adjust oven rack to middle position and heat oven to 400 degrees. Heat popovers on rimmed baking sheet until crisp and heated through, 5 to 8 minutes.