Boil the oxtail and beef skin for 10 minutes to remove impurities.
Boil again another pot of water with salt and simmer the oxtail and beef skin for 15 minutes, drain and clean the meat.
In a pressure cooker, put 8 cups of water, 1 tbsp salt,1 tbsp fish sauce and 1 tsp whole black pepper, 1 thumb ginger, 3 stalks onion leeks, 1 pack sibut and 5 pieces of bay leaves. Put back the oxtail and beef skin and let it boil for 1 hour to 1 and half hours or until the meat and skin is tender.
In a pan, heat 3 tablespoons of annatto oil then saute 1 thumb ginger(strips), 8 cloves minced garlic, chopped onions, chopped red and green bell peppers, 1 tbsp fish sauce, 1 tsp black pepper powder, 1 can black beans and 2 tbsp tomato paste.
After a few minutes add 1 cup beef broth to a boil and add 2 tbsp peanut butter(optional). Then add the oxtail and beef skin.
Add 3 cups of beef broth, bring to a boil until sauce thickens.
Served in a bowl and garnish with chopped green onions.