In a large saucepan, heat the duck fat or oil over medium heat. Add the pepper, yellow onion, carrots and garlic cloves, and sauté for 4 minutes while stirring.
Add the rest of the ingredients, except the shredded duck. Mix well. Bring to a boil and reduce the heat to low. Season with salt and pepper to taste, cover and simmer.
Meanwhile, bring water to a boil in a medium saucepan. When the water starts to bubble, immerse the bags of shredded duck (unopened) in the water and boil for 8 minutes, uncovered.
Remove the bags from the water and open with scissors, then empty the meat into a medium bowl lined with paper towels. Stir the shredded duck a little and cover with a paper towel. Press down on the duck meat to absorb some of the excess fat and remove the paper towels from the bowl.
Add the chili shredded duck meat and combine.
Continue to simmer for 20 minutes.
Serve garnished with the white onion, grated cheese and a loaf of fresh bread.
