Bend back outer petals, snapping them off at the base.
Continue snapping off petals until the leaves are half green (at the top) and half yellow.
Using a stainless steel knife, to minimize discoloration, cut the top cone of the leaves at the point where the yellow meets the green. (Green is fibrous.)
Cut the stem level with the base and trim any remaining green from the base of the artichoke. (Just like peeling the skin from an apple.)
Plunge into acidified water.
Steam whole; for stir-fry or sauté, cut in half or quarter horizontally. If there are purple or pink leaves, cut them out. (Those leaves will be tough.) If the interior is white, the entire artichoke is edible. Place in acidulated water to minimize browning while prepping.