Cook cauliflower and broccoli in boiling salted water until slightly underdone. Drain and set aside. Melt 4 tbsp. butter in 1-quart saucepan. Stir in flour and blend well. Gradually add milk, stirring constantly until thickened. Add Cheddar, Parmesan, and salt and stir over low heat until cheese melts. Place vegetables in ungreased 4 quart casserole dish and sprinkle with chopped ham. Pour cheese sauce over all. Combine bread crumbs with 4 tbsp. of butter. Make a border of buttered crumbs around edge of casserole. Bake, uncovered at 350F for 20 to 30 minutes or until crumbs are lightly browned. Yield 12 servings.