Create a roux with the butter and flour, add 2 cups heavy cream and bring to a boil while whisking. Add Knorr Low Sodium Chicken Stock Cup and whisk until incorporated. Add Milk. Remove from heat and add shredded cheddar and potatoes. Place in a 8 x 13 pan and bake at 350 for 45 minutes. Optional - top with cornflake crumbs.