Preheat the oven to 350 F. Lightly grease a 9" pie plate or quiche dish with non-stick cooking spray.
Brown the sausage in a skillet and drain.
In a mixing bowl, whisk together the eggs, milk, melted butter, salt, pepper and ground mustard.
Stir the shredded cheese and shredded hash brown potatoes into the egg mixture, then stir in the slightly cooled browned sausage.
Pour everything into the pie pan and bake in the preheated oven for 45 to 50 minutes, or until the center of the quiche is set and doesn’t move when slightly shaken.
Remove from the oven and let cool for 15 to 20 minutes.
Serve Sausage & Hash Brown Quiche warm with favorite side dishes.