Place 2 inches of water in a steamer pot and bring to a boil.
Cut top ¼ and bottom stem off of large artichokes with a serrated knife. If leaves have prickly or barbed ends, trim them off with scissors. If you are using baby artichokes, remove some of the tough outer leaves, until you hit the pale green leaves (about 10-20 leaves). Trim off top and bottom stem of baby artichokes.
Place artichokes in the steamer pot stem end down, cover and cook over medium-high heat for 30 minutes (if cooking baby artichokes cook half the amount of time) or until the leaves peel off the artichoke easily and the base of the artichoke is tender when pierced with a knife.
In a separate bowl, combine the remaining ingredients and whisk.
Serve the artichokes with the yogurt dip.
