Following the manufacturer's instructions, release the pressure using the cooker's release device, or cool the cooker by running cold water over the lid for 30 seconds. Open carefully, remove the lid, and add the vegetables, herbs, remaining salt, and pepper. Put the lid back on the pressure cooker and heat to full pressure over medium-high heat. Reduce the heat to maintain pressure and cook another 15 minutes. Release the pressure, remove the lid, and cool for 5 minutes. Serve in bowls with a few grinds of fresh black pepper and a splash of vinegar.