1. Rinse the meat and dry with paper towels.
2. Heat oil in a heavy pot. When the oil is very hot, carefully add meat and sear on all sides. Transfer to a bowl.
3. Add onion to pot and mix well to absorb the meat juices. Continue frying the onion until lightly browned. Add garlic and mix well.
4. Add chicken soup and vinegar, sprinkle with potato flour and sugar, and mix vigorously to prevent lumps from forming.
5. Return seared meat slices to the pot and add carrots, peppers, and wine. Add remaining ingredients (except shallots, if using) and mix well. Bring to a boil, lower heat, cover, and let simmer for one hour.
6. Add shallots. If there is not enough liquid, add a little boiling water. Continue cooking over low heat for another two hours until fully softened. Alternately, transfer the covered pot to an oven preheated to 320 degrees Fahrenheit (160 degrees Celsius) and bake for two hours.