Place steamer rack in large pot. Fill pot with enough water to come just to bottom of rack.
Cut stems and top 1 1/2-inches from artichokes. Cut away first outside row of artichoke leaves. Using scissors, cut off pointed tips of leaves.
Arrange artichokes on rack. Bring water to boil over high heat. Cover pot; steam artichokes until knife pierces base easily, adding more water if necessary, about 45 minutes.
Meanwhile, heat oil in small saucepan over medium heat. Add garlic; cook 1 minute. Add lemon juice and butter; whisk until butter melts. Season with salt and pepper.
Serve artichokes warm with seasoned butter.Servings: 4