1. Heat butter in a large non-stick skillet over medium heat.
2. Mix together onion, potatoes and mushrooms and add to the pan. Sauté over medium heat for 10 minutes, until lightly browned. Shake pan occasionally to prevent burning.
3. Preheat oven to 450˚F.
4. Grease a 9″ x 13″ pan.
5. Mix together hash brown mixture, sausage, eggs, jalapeños, cheese and gravy.
6. Add mixture to pan.
7. Mix together Pioneer Baking Mix, milk and bacon. Crumble mixture loosely over the top of the ingredients in the pan.
8. Bake for 25 to 30 minutes, or until top is nicely browned and biscuit mixture is baked all the way through.
9. Top with sliced green onions and serve immediately.