For a smoother sauce, you can use an immersion blender to blend the sauce after simmering. Adjust the amount of brown sugar and vinegar to suit your personal preference for sweetness and sourness. Leftover lechon can indeed be simmered in this sauce for a delicious second meal. Simply shred or chop the lechon and add it to the sauce during the last 10 minutes of simmering. Consider adding a pinch of chili flakes for a subtle kick. Freshly cracked black pepper makes a huge difference.