The original version of this recipe is called Green Lake Chicken, and it was created by my mother in order to feed the large crowds of family that would be running around our family's camp up in Green Lake, Maine. Because I've gone vegetarian for a little while (for denominational reasons — not permanently), I created this meatless version of it. Hers uses cream of chicken soup and shredded chicken, and while the mushrooms and lentils weren't a part of hers, they may become part of my non-vegetarian version.
Preheat the oven to 350 degrees.
In a medium-sized saucepan, sauté the onions and celery in 2 tablespoons of the olive oil. Season with salt and pepper, to taste. Add the vegetable stock and bring to a boil. Remove the pan from the heat and add the bag of stuffing. Stir well to dampen the stuffing and set aside.
Meanwhile, heat the remaining oil in a medium-sized sauté pan and cook the mushrooms until they've released all their juices and are well browned, about 10 minutes. Remove from the heat.
In a medium-sized bowl, mix the lentils, soup, sour cream, and onion soup mix together. Add the mushrooms and stir well to combine. In a 9-by-13-inch glass baking dish, create 1 layer using the green beans. Next, add the mushroom mixture, and then top with the stuffing. Cover the dish with aluminum foil and bake in the oven for 45 minutes. Remove the foil and bake for 15 more minutes. The stuffing should be golden brown and toasted and the mushroom mixture boiling.