Rappie Pie (Canadian Chicken)

Preheat oven to 400 degrees F (200 degrees C). Grease a 10x14x2-inch baking pan.
Heat margarine in a skillet over medium heat; add onion. Cook and stir until onion softens and becomes translucent, about 5 minutes. Reduce heat to low and continue cooking and stirring until onion is very tender and dark brown, about 40 minutes more.
Bring chicken broth to a boil in a large pot; Add chicken breasts, reduce heat, and simmer until chicken is no longer pink in the center, about 20 minutes. Remove from heat. Remove chicken breasts to a plate with a slotted spoon; reserve the broth.
Juice the potatoes with an electric juicer; Place the dried potato pulp in a bowl and discard the juice. Add salt and pepper to potatoes; Add enough reserved broth so that the mixture has the consistency of oatmeal. Reserve the remaining broth.
Spread half of the potato mixture evenly into the prepared pan. Place cooked chicken breast evenly over potatoes; spread the caramelized onion evenly over the chicken. Spread remaining potato mixture over onions and chicken to coat.
Bake in the preheated oven until golden brown, about 1 hour. Reheat chicken broth; pour over individual servings as desired.

foods：
2 tablespoons of butter
2 onions chopped
4 quarts chicken broth
1.5 kg chicken breast
4 kg of potatoes
2 tablespoons of salt
1 tablespoon black pepper