To prepare mangoes, cut a vertical slice about ¼ inch thick from either side of each stem, clearing the flat stone inside. Set each of these thick slices skin side down and score the flesh in a lattice pattern, cutting through the flesh but not the skin. Holding the mango flesh upward, push the center of the skin with your thumbs to turn it inside out, opening the cut flesh to reveal cubes. Cut the cubes from the skin. Trim remaining flesh from the stone with a knife, discarding skin.