In a large bowl, combine the salt, crushed black peppercorns, thyme, and crushed garlic. Rub this mixture generously over the duck legs, ensuring they are completely coated. Cover the bowl with plastic wrap and refrigerate for at least 24 hours, or up to 3 days.

Cooking the Duck Legs

After curing, rinse the duck legs under cold water to remove excess salt. Pat them dry with paper towels. In a heavy-bottomed pot, melt the duck fat (or heat olive oil) over low heat. Add the duck legs, ensuring they are fully submerged in fat. Cook gently for 2-3 hours until the meat is tender and easily pulls apart.

Crisping the Skin

Remove the duck legs from the fat and let them cool slightly. Preheat a skillet over medium-high heat. Place the duck legs skin-side down in the skillet and sear until the skin is crispy and golden brown, about 5-7 minutes. Remove from heat and set aside.

Mole Negro

Preparing the Chilies

Remove the stems and seeds from the dried ancho and guajillo chilies. In a dry skillet, toast the chilies over medium heat for about 1-2 minutes until they are fragrant. Be careful not to burn them.

Making the Mole

In a blender, combine the toasted chilies, chopped tomato, onion, whole garlic cloves, chicken broth, dark chocolate, cinnamon stick, and ground cumin. Blend until smooth. Pour the mixture into a saucepan and simmer over low heat for 20-30 minutes, stirring occasionally. Season with salt to taste.