Baby Artichokes à la Barigoule

• 8 baby artichokes, weighing about 1 ¼ lb. (600 g) in total
• 8 baby onions
• 4 medium mushrooms

Bring 10 cups (2.5 liters) water to a boil in a large pot.

Cut off the leaves of each artichoke about a third of the way down from the top. Cut off the stems, then remove the tough outer leaves aro