Corned Beef with vegetables

1 1/2 cups canned corned beef , cut up 1/3 cup minced celery 1/4 cup minced onion 1 teaspoon vegetable oil 2 tablespoons butter 2 tablespoons flour 1 1/2 cups[...]

1/2 cup finely chopped celery 1/2 cup finely chopped green bell pepper 1/2 cup finely chopped onion 2 tablespoons butter or 2 tablespoons margarine 8 slices[...]