Peel and cut onion to remove the center bulb and its roots. Save center and toss onion pieces in a liberal amount of olive oil and place in a oven-proof pan. Bake in center of hot oven tossing occasionally. When the majority of the pieces are crisp on the edges–golden brown–turn out onto paper towel, dry off the majority of the oil, salt and serve hot. The photo below is of quartered onions in which the center was not removed. They hold together better but they are not always cooked consistently throughout. And then, of course, there is no recycling.