Yes, it does use a lot of oil, but you can reuse it. Just put it in the fridge and use the oil for salad dressings or to fry something else in—it will add a certain “artichokiness” to your next dish. Oil keeps its heat well, so use that to your advantage here: Undercook the artichoke hearts, then keep them in the hot oil until it cools. You run a far less risk of turning them into mush that way. Do not use cheap vegetable oil (corn, canola, etc) as a substitute because you will definitely taste the olive oil in the final dish. You could use melted butter, though… Serve at room temperature. It keeps for several days in the fridge.