In a small bowl, combine vinegar, garlic, crushed peppercorn and salt. Sprinkle generously into the bangus and marinate for 30 minutes or more.
Preheat oven to 380 °F (180 °C).
Arrange the bangus in the baking tray and bake for around 15 minutes or until flaky.
Remove from oven and let cool down. De-bone the fish using clean hands (with gloves) and place in a bowl.
In a wok, heat oil and saute ginger, garlic and onion. Add celery, carrots and green bell pepper and saute for around 2 minutes.
Put the fish flakes and mix thoroughly. Cook for another 2 minutes. Season with salt, pepper and parsley. Stir until all ingredients are well combined.
Drain and transfer to a large bowl and cool completely.
After it cooled down, put the minced turnip (or singkamas) and eggs into the bowl. Mix until all ingredients are well blended.
Lay a piece of spring roll wrapper in a flat plate/ surface. Scoop 1 to 2 tablespoons of the fish mixture and arrange on the lower part of the wrapper.
Mold to form a log and press slightly to compress the mixture. Secure the filling by folding both sides of the wrapper inward and roll from the bottom to top. Wet the pointed edge of the wrapper with water to completely seal. Do this to the remaining mixture.
Using a skillet, heat oil and fry the lumpia rolls. Make sure to leave extra space in the pan to equally cook the rolls. Cook each side for 2 to 3 minutes or until golden brown.
Transfer to a cooling rack to let the extra oil drip. Serve with your favorite dipping sauce.
To make the spicy vinegar sauce: Combine all the ingredients in a mixing bowl. Stir until well blended.
To make the sweet and sour/ fish ball sauce: Mix all the ingredients except chili in a sauce pan. Whisk until sugar and cornstarch are dissolved. Turn on the heat in low and continue to whisk. Stir until the sauce starts to thicken, around 1-2 minutes. Then add the chili and remove from heat.
Share and enjoy!