Preheat oven to 350 degrees F (175 degrees C).Advertisement
In a small pan, melt butter and add onions. Cook 10 to 15 minutes or until soft. Remove onions from pan (leave butter in pan) and place in a 9x13 inch pan.
Combine soup and milk to pour over onions. Sprinkle with cheese. Slice bread approximately 1 1/2 inches thick and dip both sides in butter. Arrange on top of cheese. Bake for 30 minutes or until bread is golden brown and toasty!