Using a sharp knife, cut about 1-inch off the top of the artichoke. Cut off the stem. Snip sides to remove the barb.
In a medium-size pan, boil two cups of water and place the artichokes stem side down in a steamer basket or rack.
Allow to steam for 45 minutes.
While steaming the artichokes, make the aioli dipping sauce by combining mayonnaise, garlic, lemon juice, lemon zest, salt, and pepper. Serve in a ramekin alongside the steamed artichokes.
