Step 1

To prepare pot roast: Heat 2 teaspoons oil in a 4-quart or larger pressure cooker over medium-high heat. Add onions; cook, stirring often, until softened and starting to brown, 3 to 5 minutes. Add garlic, rosemary and orange zest; cook, stirring, until fragrant, about 10 seconds. Remove from heat.

Step 2

Sprinkle beef with 1/4 teaspoon salt and pepper. Heat the remaining 1 teaspoon oil in a large skillet, preferably cast-iron, over medium heat. Add the beef; cook, turning from time to time, until well browned on all sides, 5 to 8 minutes (see Tip). Transfer the beef to the pressure cooker, nestling it among the onions. Add wine to the skillet; bring to a boil, stirring to scrape up browned bits. Cook, stirring, for 1 minute. Add broth and bring to a simmer. Pour the mixture over the beef in the pressure cooker.

Step 3

Secure the pressure cooker lid. Bring to high pressure over high heat following the manufacturer's directions. Reduce the heat to the lowest setting that maintains high pressure. Cook for 1 1/2 hours if using bottom round or rump, 1 hour if using chuck.

Step 4

Let the pressure release naturally. This will take 5 to 20 minutes. Check the roast: it should not show any resistance when pierced with a sharp knife. If it is not tender, secure the lid and return to high pressure. Cook 5 minutes, release the pressure naturally, then check again.

Step 5

To prepare mustard sauce: Meanwhile, combine mayonnaise, yogurt, mustard and pepper in a small bowl.

Step 6

Transfer the roast to a clean cutting board. Cover loosely with foil and let rest for 5 to 10 minutes. Skim fat from the liquid in the cooker. Bring to a simmer over medium-high heat. Combine cornstarch and water in a small bowl; add to the liquid and cook, whisking, until the gravy thickens slightly, about 1 minute. (If you want it thicker, combine an additional 2 teaspoons cornstarch with 1 tablespoon water and stir into the simmering gravy until thickened.) Season to taste with salt and pepper. Slice the meat and serve with the gravy and the mustard sauce.

Step 7

Conventional-Stove Variation: Preheat oven to 325F. In Step 1, replace the pressure cooker with a 4- to 6-quart Dutch oven. After sauteing onions, garlic, rosemary and orange zest, transfer to a plate. Brown the meat (Step in the same pot. Add the onion mixture back to the pot along with the broth. Press a piece of parchment paper directly on the surface and cover the pot with a lid. Transfer to the oven and bake until the beef is tender, 2 1/2 to 3 hours.