Note: Recipe courtesy of Everyday Food chef Allie Lewis.
Prepare artichokes for steaming: Snap off tough outer leaves. Using a serrated knife, cut off top 1/3 of artichoke. Snip remaining sharp or spiky tips using kitchen shears. Trim stem so artichoke stands upright. Rub cut surfaces with lemon to prevent discoloration. Repeat with remaining artichokes and lemon.
Set a steamer basket in a large pot; add enough water so it reaches just below the basket. Squeeze lemon juice into water and add 1 tablespoon salt; bring to a boil. Place artichokes in steamer basket, stem-side up. Cover pot, and steam until heart is tender when pierced with a tip of a paring knife, and inner leaves pull out easily, 25 to 35 minutes; add more water to pot, if necessary. Serve warm or at room temperature with dipping sauce, if desired.