Place sausage in a large, deep skillet. Cook over medium-high heat until evenly brown. Drain, and set aside. Melt butter in skillet, and cook and stir the green onions and mushrooms until tender.
In a large bowl, mix the eggs, cottage cheese, Monterey Jack cheese, and chiles. Stir in the sausage, green onions, and mushrooms. Cover, and refrigerate overnight.
Preheat oven to 350 degrees F (175 degrees C). Lightly grease a 9x13 inch baking dish.
In a bowl, sift together the flour, baking powder, and salt. Blend in the melted butter. Stir the flour mixture into the egg mixture. Pour into the prepared baking dish.
Bake 40 to 50 minutes in the preheated oven, or until lightly brown. Let stand 10 minutes before serving.
