Oyako donburi—chicken and egg cooked with onion and seasonings and served on top of steaming-hot rice—is Japanese comfort food and a satisfying meal in a bowl. The chicken and egg mixture customarily is made in individual portions in a small pan, but we use a 12-inch skillet to make a simplified family-style version that we then spoon onto bowlfuls of cooked rice. Dashi, or stock made with seaweed and, typically, shaved dried bonito, lends the dish an umami-richness and a distinctly Japanese flavor. You can make the stock from scratch, but instant dashi, sold in packets in many well-stocked supermarkets, is a convenient option. Otherwise, low-sodium chicken broth works well in its place.