Simmer beef in water until it is tender. Set aside the broth. Boil potato in beef broth and set aside. Boil plantain and set aside. In a large skillet or saucepan, sauté garlic in oil. Add beef, chorizo or pepperoni, chick peas, broth, green beans, cabbage and green onions or scallions. Add quartered onion and peppercorns. Simmer until vegetables are done. Add salt to taste. When ready to serve, garnish with banana and potato. Serve with pochero sauce. To make pochero sauce, boil eggplant and remove skin. Mash with plantain and sweet potato. In a pan over heat, add the vinegar, garlic, salt and pepper. Mix well.