This hearty soup is served over tender Chinese wheat noodles. To prepare the noodles while the soup is cooking, bring 4 quarts water and 2 tablespoons kosher salt to a boil. Add the noodles and cook according to package directions. You’ll need to keep an eye on the pot and stir frequently to prevent the noodles from boiling over. Toast the Sichuan peppercorns in a small skillet over medium until fragrant. Start timing the soup once it has reached high pressure.

Don’t cut the beef into pieces any larger than 1 inch or they won’t tenderize in time. Be sure to rinse the noodles after cooking to remove excess starch.

In a 5½-liter or larger pressure cooker over medium-high, heat the oil until shimmering. Add the ginger, garlic and scallion whites. Cook, stirring, until fragrant, about 30 seconds. Stir in the bean sauce, tomato paste, ground peppercorns, five-spice powder and sugar, then cook until fragrant, about 1 minute. Stir in the sherry and cook until nearly evaporated, about 1 minute. Stir in the water, soy sauce and beef. Lock the lid in place and bring to high pressure (second red line). Adjust heat to low to stabilize the pressure at the second red ring. Cook for 20 minutes.

Off heat, allow the pressure to reduce naturally for 10 minutes, then quick release the remaining pressure. Carefully open the lid an tilt it away from you to release the residual steam. Stir in the bok choy and simmer over medium until tender, about 3 minutes. Stir in the lime juice, taste, then season with additional soy sauce, if needed. Divide the noodles among serving bowls, ladle the hot soup over the noodles and sprinkle with scallion greens.