Set potatoes out to thaw.
In a skillet melt butter of med heat. Whisk in flour and let bubble for one minute. Slowly stir in milk and broth. Add in seasonings. Then thickened turn off heat and let cream of chicken cool a little.
In large bowl add potatoes, 1 ½ cup sharp cheddar cheese, sour cream and cream of chicken. Stir together until well combined.
Place in 9x13 pan and top with remaining cheese and corn flakes.
Bake at 350 for about 45 minutes or until top is golden.
