Clean all offal thoroughly under running water until the water runs clear. In a large pot, add the cleaned offal, bay leaves, and whole peppercorns, then cover with water. Bring to a boil over high heat (200°C). Once boiling, reduce heat to medium-low (150°C) and simmer for 2 hours or until the offal is tender when pierced with a fork. Remove offal from the pot and cut into bite-sized pieces.

Heat annatto oil in a heavy-bottom pan over medium heat (170°C). Add minced garlic and sauté for 30 seconds until fragrant. Add chopped white onions and cook for 2-3 minutes until they become translucent. Add the cut offal pieces to the pan and stir-fry for 2-3 minutes to let them absorb the flavors.

Pour in the beef stock and vinegar. Let the soup simmer for 20 minutes over medium-low heat (150°C). Taste and season with salt and pepper until you're happy with the flavor. Once done, ladle the hot soup into serving bowls. Top each bowl with chopped green onions and sliced bird's eye chilies for garnish. Serve immediately while hot.

To serve traditionally, place extra chilies and patis (fish sauce) on the table so everyone can adjust the heat and saltiness to their taste. For best results, enjoy with hot steamed rice or as pulutan (appetizer) with ice-cold beer.

Note: Remember to remove any scum that rises to the surface during the initial boiling of the offal for a cleaner-tasting soup.