Beat the eggs, and add evaporated milk, soup, dry mustard, salt, and pepper. Set aside.
Line the bottom of a 9 x 13 pan with frozen hash browns. Top with browned sausage. Pour egg mixture over the hash browns and sausage. Place in oven and bake for approximately 40 minutes. Check by placing a knife in baked casserole. When knife comes out clean, casserole is done.