Melt butter in a large stockpot. Add onions. Cook 5 minutes or until soft. Stir in flour. Whisk in milk until smooth. Bring to a boil, stirring until thick. Remove from heat and stir in 3/4 cup cheddar, swiss, and sour cream. Stir in cauliflower, carrots and ham. Pour into 13X9 baking dish. Top with bread crumbs and remaining cheddar. Bake at 350 for 40 minutes.
Whole Grain Bread Crumbs
Process bread slices in a food processor or blender until fine crumbs. Approximately 1 c.
Try to find uncured ham with no nitrates and no sugar.