Put the beans in a bowl, cover with water, and soak overnight. The next day drain the beans and transfer to a saucepan with water to cover. Bring to a boil, turn the heat to medium and cook partially covered with a lid, for 1 hour or until the beans are soft. Add salt to taste.
When the beans are ready, heat a frying pan with the olive oil over medium heat, add, and saute 2 onions cut in thick slices, from root to top, and 3 chopped garlic cloves, together with the ají panca and ají amarillo, bay leaves, vinegar, cumin, salt and pepper. Cook for 5 minutes, then add the vegetable stock and cook for 5 more minutes.
Strain the beans and put in a serving dish. Top with escabeche sauce and serve over a lettuce leaf, garnished with black olives, and, if desired, hard-boiled egg halves.
Recipe by PERU DELIGHTS at https://perudelights.com/beans-with-escabeche-sauce/