Step 1

In the large pot over medium, heat 1 tablespoon oil, the onion and ½ teaspoon salt. Cook, stirring occasionally, until the onion is well browned, about 10 minutes. Add the tomato paste, then cook, stirring, until it begins to darken and stick to the bottom, about 5 minutes. Stir the broth, bay and thyme, then add the beef. Bring to a simmer over medium-high, then cover, reduce to low and simmer gently, stirring occasionally, until a skewer inserted into the beef meets no resistance, about 2½ hours.

Step 2

When the beef has simmered for about 1½ hours, make the popover batter. In a large bowl, whisk the eggs until well combined. Gradually whisk in the milk. Add the flour and salt, then whisk until just combined; do not overmix. Whisk in the melted shortening. (If desired, for easy pouring, transfer the batter to a 1-quart liquid measuring cup.) Cover and let stand at room temperature until ready to use.

Step 3

Meanwhile, heat the oven to 400°F with a rack in the middle position. Using shortening, lightly grease the 10 outer cups of a 12-cup nonstick standard muffin pan (leave the center 2 cups ungreased, as they will not be used). Dust the cups with flour, then tap out the excess.

Step 4

When the beef is done, remove the pot from the heat. Using a slotted spoon, transfer the beef and onion to a medium bowl; set aside. Remove and discard the bay and thyme. If you wish to reduce the cooking liquid for enriching the sauce, pour the cooking liquid into a fat separator, then pour the juices back into the pot along with any liquid accumulated in the bowl; discard the fat. Bring the liquid to a simmer over medium-high; cook, uncovered and stirring occasionally, until reduced to ½ cup, 5 to 8 minutes. Remove from the heat and set aside. Shred the beef into bite-size pieces, retuning it to the bowl with the onion, and set aside.

Step 5

Stir the popover batter to recombine, then divide it evenly among the prepared muffin cups. Bake without opening the oven door until the popovers are well risen and deeply browned, about 45 minutes. Working quickly, open the oven door and, using a wooden skewer, poke a hole in each popover. Close the oven door and bake for another 1 minute.

Step 6

While the popovers bake, make the cream sauce. In a large saucepan over medium, melt the butter. Add the flour and cook, whisking constantly, until the mixture begins to brown, about 5 minutes. Gradually whisk in the milk, followed by the reduced beef cooking liquid, if using, then add the bay and thyme. Bring to a simmer, whisking constantly, then cook, uncovered and whisking occasionally, until the sauce is thick enough to coat the back of a spoon, about 10 minutes.

Step 7

Add the shredded beef and onion to the sauce; cook, stirring constantly, until heated through, about 2 minutes, thinning with more milk, if needed, to reach the desired consistency. Off heat, taste and season with salt and pepper. Remove and discard the bay and thyme.

Step 8

When the popovers are done, remove the pan from the oven. Using tongs, immediately and gently transfer each popover to a wire rack. Let cool for about 5 minutes. Meanwhile, rewarm the beef in cream sauce over medium, stirring occasionally, until heated through, 3 to 5 minutes.

Step 9

To serve, use a serrated knife to cut a slit vertically in the top of each popover and gently pry it partially open. Place on individual plates and spoon the beef in cream sauce into the popovers. Sprinkle with the chives.