In a large, deep saucepan with a lid, heat the olive oil over medium heat. Add the anchovies, garlic and crushed red pepper and cook until the garlic begins to soften, 3 to 5 minutes.
Meanwhile, thoroughly wash the broccoli rabe, then add it to the saucepan with the water still clinging to it. Cover the pan tightly and cook until the broccoli rabe is tender and just a few spoonfuls of water remain, about 15 minutes. Season to taste with salt and top with the olives.