Melt 3 tb of butter. Stir in flour, salt, pepper, sugar, and onion.
Add sour cream gradually. Cook until thickened. Fold in green beans;
heat thoroughly. Pour into greased casserole a layer of bran mixture,
then a layer of grated Swiss cheese and another layer of green bean.
Finish with grated cheese on top. Mix cornflakes in 2 tb melted
butter and sprinkle on top. Bake at 400°F for 20 minutes.