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.

Sprinkle Garlic in between leaves. 

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 melted butter and lemon if desired.