1. 1. Cook the sausage: Begin by cooking the sweet Italian sausage links in a skillet over medium heat until they are browned and cooked through. Remove the sausage from the skillet and slice it into bite-sized pieces.

2. 2. Make the sauce: In the same skillet, melt the butter. Whisk in the all-purpose flour, dry mustard, and kosher salt, then gradually add the whole milk. Cook the sauce, stirring constantly, until it thickens to your desired consistency.

3. 3. Cook the hash browns: Prepare the shredded hash browns according to the package instructions, cooking them until they are golden and crispy.

4. 4. Assemble the stacks: In a baking dish or skillet, layer the crispy hash browns, sliced sausage, eggs, and shredded cheddar cheese.

5. 5. Bake to perfection: Preheat your oven to 350°F and bake the stacks until the eggs are set and the cheese is melted, about 15-20 minutes.