Bring 3 cups water and 1 cup mung beans to simmer in a covered pot approximately 25-30 minutes until beans are soft. Add 2 cups water and 1 1/2 cup couscous to another pot and simmer uncovered for 8-10 minutes until tender. Combine, set aside and allow to cool.
Toast pine nuts in skillet until lightly brown and set aside. Add 1 tsp butter to the skillet and add the diced onion. Allow to cook until lightly browned and add the mushrooms. Cook until the mushrooms have reduced to half the size and are tender. Add the remaining vegetables except the beets and cook until tender.
In the meantime, boil the sliced beets 8-10 minutes until tender. Once cooked, add to the skillet along with the remaining ingredients, including the butter.
Combine couscous/mung bean mixture, pine nuts, and vegetable mixture. Season with salt and pepper to taste. Serve with nutritional yeast sprinkled on top.