Prepare the filling: Boil water in a saucepan.

Add pork, onion, celery, salt, and pepper to the boiling water and simmer for 20 minutes.

Remove pork and let it cool.

Reserve the broth.

Slice the cooled pork into cubes.

Cut the heads off shrimp and peel the shells.

Process shrimp heads and shells in a food processor.

Refrigerate the mixture for 1 hour, then strain.

Devein and julienne shrimp bodies.

Heat oil in a skillet or wok and cook the pork until browned and crisp.

Remove pork and drain on paper towels.

Sear tofu in the same oil until lightly browned.

Drain tofu and pat dry.

Slice tofu into small cubes.

Sauté onion and garlic until softened.

Add cabbage, carrot, and string beans and sauté until slightly softened.

Season with salt and pepper.

Pour in reserved shrimp juice and pork broth and simmer.

Add fish sauce, pork, shrimp, tofu, and jicama.

Cook until shrimp are cooked through.

Taste and adjust seasoning.

Cool the filling and refrigerate for at least 1 hour or overnight.

Drain the cooled filling to remove excess moisture.

Assemble the spring rolls: Place spring roll wrappers on a baking sheet and cover with a damp towel.

Cut a stack of wrappers into equal squares.

Place a whole wrapper with a corner pointed toward you.

Place a smaller square in the middle and add filling.

Fold the wrapper over the filling, tucking the end underneath the smaller square.

Fold the right and left sides over the filling.

Seal the edges with beaten egg yolk.

Cover the completed spring rolls.

Fry the rolls in batches in hot oil until golden brown.

Drain on paper towels.

Serve hot with a dipping sauce made of vinegar, garlic, and chiles.