First things first: Never, but never, be tempted to swap in nonstick cooking spray for the melted butter when making popovers. Especially not this popover recipe, which was first printed in the July 1957 issue of Gourmet and was so popular with readers and editors alike that it appeared again in the 1991 anniversary issue dedicated to the magazine’s all-time best recipes. Glossing the tin with butter gives the eggy, airy puffs a rich, toasty flavor—and with such a simple batter, every ingredient counts. If you don’t have a popover tin, however, there are workarounds. Grab a 12-cup muffin pan or six 5-oz. ramekins; as long as you fill them only half full, you’ll be fine. The popovers won’t be as dramatically shaped, but they’ll still taste delicious. It’s a good idea to place whatever vessel you use on a sheet pan for easy maneuvering in and out of the oven. (No tins or cups? Try making Yorkshire pudding, a similar dish baked in a casserole.)
Oven temperature here is key. Other than eggs, popovers have no leavening, so the heat is crucial to their rise. Preheating the pan creates that signature crispy-on-the-outside, custardy-within texture. Many ovens are unreliable narrators, so consider investing in an oven thermometer if yours runs hotter or colder than the set temperature. When it’s time to add the popover batter to the hot pan, work quickly with the oven door closed to keep heat from escaping. And remember, even the most perfect popovers can stiffen or deflate as they cool, so be sure to bake them just before serving and bring them to the table piping hot.