This is an excellent way to preserve nutrients
Place wire rack on bottom of a kettle or large saucepan and add water to just below the level of the rack. Bring the water to a boil, add potatoes and cook, tightly covered, until fork-tender (whole potatoes 30-45 minutes, cut-up, 20-30 minutes). Check occasionally to see if water should be added, if lid is not tight fitting)
Note: If rack isn’t available, invert custard cups or crumple aluminium foil to make an elevated platform.