Creamy Cheese Cauliflower Casserole

1 head cauliflower
1 teaspoon salt
3 tablespoons butter
3 tablespoons flour
1/4 teaspoon salt
1 cup milk
1 cup grated cheese

Wash and cook cauliflower in boiling salted water until tender; drain. Melt butter in saucepan, blend in flour and salt and stir until well mixed. Cook 1 minute. Remove from heat, add milk all at once. Cook over low-to-medium heat stirring constantly until thickened. Add cheese, reserving 1/4 cup, and continue stirring until it melts. Pour sauce over cauliflower in casserole pan, then sprinkle remaining cheese over top. Bake i moderate oven for 30 minutes.