In a saucepan, melt butter over medium heat. Whisk in flour until smooth, cooking for 1-2 minutes.
Gradually whisk in chicken broth until no lumps remain. Then, slowly whisk in milk until incorporated.
Continue whisking over medium heat until the mixture thickens, about 3-5 minutes. Season with salt and pepper to taste.
Hash Brown Casserole
Preheat oven to 350°F (175°C).
In a large bowl, combine thawed hash browns with melted butter, ensuring even coating.
Gently stir in the prepared cream soup substitute, sour cream, diced onion, cubed ham, and 1 ½ cups of shredded cheddar cheese. Season with salt and pepper to taste.
Transfer the mixture to a lightly greased 9x13 inch baking dish. Sprinkle the remaining ½ cup of cheddar cheese evenly over the top.
Cover the dish with foil and bake for 1 hour. Remove the foil and bake for an additional 15 minutes, or until the cheese is bubbly and golden brown.