1 (4-pound) center-cut pork roast, ribs cracked (see Note)
1 teaspoon salt
1½ teaspoons black pepper, divided
2 tablespoons vegetable oil
1 medium-sized onion, cut into ¼-inch slices
2 cups water
2 medium-sized yellow squash, cut into 1½-inch chunks
1 medium-sized zucchini, cut into ½-inch chunks
2 cans (15 ounces each) whole potatoes, drained
1 teaspoon onion powder
Sprinkle the pork with the salt and 1 teaspoon pepper. Heat the oil in a 6-quart pressure cooker over medium-high heat. Brown the pork roast, uncovered, for 8 to 10 minutes. Place the onion slices over the roast and add the water. Lock the lid in place and bring to full pressure over high heat. When the pressure regulator begins to rock, reduce the heat to medium and cook for 45 to 50 minutes. Cool cooker at once by placing under cold running water until steam no longer escapes from the vent pipe and the pressure is completely reduced.
Remove the lid and place the roast on a covered serving platter to keep warm.
Add the remaining ingredients, including the remaining 1/2 teaspoon pepper, to the pressure cooker. Cook, uncovered, for 8 to 10 minutes over medium-high heat, or until the vegetables are fork-tender. Slice the roast and serve with the vegetables and cooking liquid.
Make sure to ask the butcher to crack the ribs on the pork roast for you – it makes cutting the roast much easier. Or, if you prefer, use a boneless pork roast.