In a large mixing bowl, combine ½ kg ground pork, 2 grated carrots, 3 minced garlic cloves, 1 finely chopped onion, 1 finely chopped celery stalk, and 2 finely chopped spring onions (optional).

Add 2 tablespoons of soy sauce, 1 beaten egg, salt, and pepper to the mixture. Stir well until all ingredients are fully combined.

Heat a small amount of oil in a pan and fry a small portion of the filling to taste. Adjust the seasoning by adding more salt, pepper, or soy sauce if needed.

Lay a lumpia wrapper flat on a clean surface, with one corner pointing towards you (forming a diamond shape).

Spoon about 1 to 1½ tablespoons of the prepared filling onto the wrapper, near the corner closest to you.

Fold the bottom corner of the wrapper over the filling, then fold in both sides.

Roll the wrapper tightly towards the top corner, sealing it by using a small amount of the flour and water mixture (1 tablespoon flour mixed with 2 tablespoons water)

Repeat this process for the remaining lumpia wrappers and filling.

Heat enough cooking oil in a deep frying pan to submerge the lumpia. The oil should be at medium heat, around 350°F or 175°C.

Carefully place the lumpia into the hot oil in small batches. Fry them for 3-5 minutes, turning occasionally, until they are golden brown and crispy on all sides.

Remove the cooked lumpia from the oil and place them on a plate lined with paper towels to drain any excess oil.