Cook onion in drippings until tender but not brown. Stir in the flour, sugar, salt and pepper. Add water and vinegar. Cook and stir until thickened. Pour over potatoes and add bacon.
Dice pears and set aside.
Dissolve jello in boiling water. Chill until set but not firm, about 1 hour. Meanwhile, soften cream cheese. Very slowly, blend in remaining gelatin, beating until smooth. Stir in pears.