The stock amount and cooking time will vary slightly, depending upon the type of short-grain Italian rice you use. Author Lorna J. Sass finds that arborio works will with 3 1/2 cups of stock, while Vialone Nano and Carnaroli usually require 1/2 cup more stock and about a minute of additional cooking in an uncovered cooker.
Heat the oil in the pressure cooker. Add the shallots and cook over high heat until just translucent, about 30 seconds. Add the rice and stir to thoroughly coat with oil. Add the wine and stir constantly until it has evaporated, about 1 minute. Stir in 3 1/2 cups of the stock, the salt and the saffron.
Lock the lid in place and bring to high pressure over high heat. Lower the heat just enough to maintain high pressure and cook for 5 minutes. Reduce the pressure with a quick-release method. Remove the lid, tilting it away from you to allow any excess steam to escape.
Give the risotto a vigorous stir. If the rice is still a bit too hard or the risotto is too soupy, cook it over moderately high heat, stirring constantly, until the desired texture and consistency are reached. Add the remaining 1/2 cup of stock if necessary. Stir in the Parmesan and parsley and season with pepper. Serve immediately in shallow bowls.