Directions

1. Preheat oven to 400 degrees F (200 degrees C).
2. Place the mung beans in a saucepan and cover with water. Bring to a boil over medium-high heat, and cook for 10 minutes. Lower heat to medium, and simmer until soft, about 10 minutes. Drain beans into a strainer and rinse under cold water. Set aside.
3. Meanwhile, place the potatoes in saucepan, cover with water, and stir in 1/4 teaspoon salt. Bring to a boil over medium-high heat, and cook just until potatoes begin to soften when pierced with a fork, about 10 minutes. Drain, and set aside.
4. Heat the oil in a skillet over medium heat. Add the onion; cook and stir until transparent, about 5 minutes. Add the carrots, celery, and mushrooms. Cook and stir until the vegetables are tender, about 5 minutes. Pour in the stock, and add salt and pepper to taste. Cook vegetable mixture 5 minutes more. Combine with the mung beans and potatoes in an oven-proof casserole. Cover with a lid.
5. Bake in preheated oven until mixture bubbles, about 30 minutes.