There is a story in the Gemara (or maybe Midrash) about a man who would say he wants peas for dinner, but his son would tell his mother the father wanted lentils, and when the man would tell his son he wanted lentils, his son would tell his mother that the father wanted peas.
This probably indicates that (dried split) peas or lentils were common dinner dishes. Dried peas and lentils are extremely cheap, nutritious and easy to cook. They are very high in protein and iron, and other important vitamins and minerals. Our ancestors probably only ate meat once a week on Shabbos (given statements about the frequency of meat eating in the Gemara, many people probably ate it much less frequenlty).
I like to make soups with some kind of lentils and some kind of grain (brown rice, buckwheat, couscous), and add vegetables such as potatoes, sweet potatoes and carrots. It can be seasoned simply with olive oil, salt and pepper, or other spices if desired, and it’s good to add lemon juice to each person’s bowl just before serving. A big bowl of hot soup like this can even make good breakfast food (studies show people do better in terms of energy and weight gain when eating a big meal for breakfast).
I can’t get my small children to eat such food, but I know of an Israeli who feeds her whole family lentil vegetable soup nearly every day.