How much involvement by a Jew is required to avoid the status of Bishul Akum?

There is a dispute among the early codifiers whether bishul akum is negated by a Jew initiating the entire cooking process (i.e. by placing the food in the oven or on the stove top, or by turning on the fire after the food is on the stove), or whether it is sufficient for the Jew to partially contribute to the cooking of the food (i.e. turning on the fire, even though the non‐Jew subsequently places the pot on the fire, raises the temperature of the fire or adds a woodchip to the fire). Rav Yosef Cairo, author of the Shulchan Oruch supports the stringent position (Yoreh Deah 113:7), while the Ramo concurs with the lenient view. Jews of Sephardic descent generally follow the Shulchan Oruch, while Ashkenazic Jews adhere to the Ramo.