Add the ground beef and diced onion to a large skillet and cook over medium-high heat until no pink remains.
1 Pound Ground Beef, ½ Each Yellow Onion
Add to a large mixing bowl, along with the shredded hashbrowns, pepper jack cheese, cream of mushroom soup, sour cream, milk, salt and creole seasoning. Stir to combine.
15 Ounces Shredded Hashbrown Potatoes, 1 Cup Pepper Jack Cheese, 10 Ounces Cream of Mushroom Soup, ¾ Cup Sour Cream, ¼ Cup Milk, ½ teaspoon Salt, 1 teaspoon Creole Seasoning
Empty into a 11x7" Casserole Dish, evenly, and bake in the oven for 30-35 minutes until bubbling around all edges.
Top with the remaining colby jack cheese and bake again another 5 minutes.