Preheat oven to 350°F (180°C).
Heat oil in a large frying pan over medium heat. Sauté onion until soft and golden.
Add remaining vegetables and continue sautéing until soft.
Place vegetables, seasonings, couscous, and boiling water in a 9- x 13-inch pan. Stir.
Cover and bake for one hour.
This recipe can be frozen. For best results, sauté vegetables, combine with spices, and freeze. On Yom Tov, just add the couscous and boiling water and bake fresh.