Preheat convection oven to 350˚F with high fan and prepare two half hotel pans with non-stick spray. Set aside.
Prepare Pioneer® Country Gravy according to package directions and set aside to cool.
In sauté pan, brown and crumble breakfast sausage, then drain fat. Add butter to pan and melt. Add onions and sauté until translucent. Set aside.
In a large bowl, whisk together all 12 eggs until smooth. While whisking, gradually add 2 quarts cooled Pioneer® Country Gravy to eggs to temper the eggs without curdling them. Add hash brown potatoes and green onions, whisking to combine.
In prepared half hotel pans, line the bottom of each pan with split Conestoga® Simple Split Buttermilk Biscuit halves, cut side up. Top with cooked sausage and onion mixture. Sprinkle ½ lb. of cheddar cheese in each pan on top of sausage and onion mixture.
Pour gravy and egg mixture evenly into pans on top of cheese. Use remaining cheese to top gravy and egg mixture.
Cover each pan with foil and bake for 20 minutes, then uncover and cook for another 10 minutes, until cheese is golden brown.