Wash cabbage thoroughly. Slice and chop coarse.Place cabbage into a large size pot and add enough water to cover.
Bring to a boil and cook until tender. Drain well.
In a medium saucepan add 3 Tbsp melted butter, flour and salt.
Add milk slowly to sauce pan.
Stir until sauce boils and thickens. Remove from heat.
Layer cabbage in buttered casserole, pour some sauce over it and sprinkle it with cheese.
Repeat layering until all ingredients have been used.
Top with cheese.
Blend bread crumbs with 2 Tbsp melted butter and put on top of casserole.
Bake at 350° until brown (about 25 minutes).