Potato kugel is a variation on kugel eaten by many Ashkenazi Jews as a side dish on the Sabbath. It is a casserole typically containing grated or ground potatoes, onions, eggs, flour or matzo meal, oil, salt and pepper.Some modern cooks add a small amount of baking powder. In addition to lightening the dish, the powder's alkaline chemistry breaks down the potatoes and produces a smoother texture while promoting browning.