Place croutons in a greased 3 qt baking dish. Sprinkle with cheese and ham. In a large bowl, whisk the eggs. 2 1/4 cups milk, mustard and hot sauce. Pour over cheese and ham. Cover and refrigerate over night.
Remove from fridge. Combine remaining milk and soup until blended and pour over casserole. Top with hashbrowns, paprika and pepper.
Cover and bake for 30 minutes at 350 degrees. Uncover; bake an additional 40 minutes--edges should be brown. Let stand for 10 minutes before serving.