In a large pan over medium heat, add the cooking oil, sauté the garlic and onion until soft and translucent. Add the pork and cook for 7 minutes or until lightly brown.

Add the soy sauce, oyster sauce and brown sugar. Stir until the sugar is dissolved. Simmer for 2-3 minutes.

Pour the cornstarch mixture then season with salt and pepper. Simmer for 1 minute or until the sauce thickened. Remove from the pan, let it cool and set aside.

In a large bowl, combine the flour, baking powder, sugar, butter and milk. Gradually add the water while continuously stirring until well blended.

Prepare the molders and grease with vegetable oil or melted butter. Pour about 1 tablespoon of batter mixture on each mold.

Then, put a teaspoonful of asado filling on each mold. Add some more batter up to 3/4 full and top with a slice of salted duck egg.

Place in a steamer basket and steam for 10-15 minutes over boiling water. Remove from the steamer and let it cool for 10 minutes. Gently loosen the Puto Pao from mold and serve.