Ingredients

1.5 kg. pork belly, sliced 1 inch thin (Asado style)
2 tbsps. of black bean sauce or salted black beans (tausi), rinsed and grounded
3 sprigs of oregano or 2 tsp dried oregano
1 whole garlic
4 shallots (sibuyas Tagalog) or 2 small onions
1 cinnamon stick or 2 tsp cinnamon powder
1 star anise
salt, optional
2 tbsp brown sugar
3 tbsps. of cooking oil
1/4 cup peanuts small pieces
6 pcs big or 12 pcs small Manthao (store-bought)

Procedure:

1. Heat the cooking oil in a non-stick pan.
2. When hot, place the cut pork belly and cook until lightly brown. (If overcooked, the pork will get hard.)
3. Add the rest of the ingredients except for the brown sugar, peanuts and manthao, pour enough water to cover three quarters of the pork, bring to the boil, then lower the heat, cover and simmer until the pork is tender. Add the brown sugar and let it simmer for a while. Add more water if the sauce dries up before the pork is done. Cook the pork until the sauce is reduced and thickened.
4. Fold in the small peanut pieces.
5. Wait for the filling to cool.
6. Meanwhile, slice the manthao into two so that you could put in the filling later.
7. Place the manthao in the steamer and steam for 10-15 minutes.
8. Put the filling on the bottom layer of manthao, just enough amount to cover it, and place the other half on top. Do this for the remaining manthao.

Serve and share it with family and friends!

Source: Casa Veneracion 
I have added some ingredients and altered the procedure from the recipe of Ms. Connie Veneracion.