It seems that every Jewish occasion is somehow associated with food. The Jewish cookbooks that I own even have special sections for Yom Kippur and other fast days, because, well, du'h: you have to eat before and after the fast. They wouldn't want that we should starve.
It is customary to refrain from eating meat during the nine days before Tisha B'Av (except Shabbat) as a sign of mourning.* However, mourning (like Yom Kippur) has positive gastronomic traditions as well. Lentils and hard-boiled eggs are often eaten on account of their round shape, which symbolizes a closed mouth and/or the cycle of life. Mengedarrah, a simple combination of lentils and rice, is a traditional Nine Days food among Middle Eastern Jews. (Egyptians call it koshari.) This information,** and the following recipe for mengedarrah, come from Gil Mark's World of Jewish Cooking. (I've tried it. It's good.)
1 pound (about 2 cups) green or red lentils
1/4 cup vegetable or olive oil
2 medium yellow onions, chopped (about 1 cup)
2 cups rice
4 1/2 cups water
About 1 1/2 tsp salt
Ground black pepper to taste
Fried onions or yogurt for garnish
1. Rinse the lentils and soak in water to cover for at least 2 hours. Drain.
2. Heat the oil in a medium saucepan over medium-high heat. Add the onions and saute until golden brown, 10 to 15 minutes. Stir in the rice and saute until well coated, about 1 minute.
3. Add the lentils, water, salt, and pepper. Bring to a boil, cover, reduce the heat to low, and simmer until tender and the water is absorbed, about 30 minutes.
4. Remove from the heat and let stand covered for 5 minutes. Stir with a fork to fluff. Transfer into a large serving platter and scatter fried onions over the top or serve with yogurt.
*The Nine Days began today.
**Meaning, the information relating directly to lentils and mengedarrah.