Put the beef and pork in a large bowl and gently mix to combine.

Add the garlic, ginger, water chestnuts, carrot, Spanish onion, soy sauce, sesame oil, salt, black pepper, chili flakes, and scallion and mix until combined.

Take half of a wrapper and place it on your work surface so that a point is facing you. Place about 2 heaping tablespoons of the filling on the wrapper and spread it out to the edges. Turn up the bottom corner and roll upward. Fold in the left and right corners, making sure the filling is nicely packed, with no air pockets. Continue rolling. Dip your finger in egg wash, pat it on the remaining corner, and finish rolling the lumpia, sealing the edge.

The lumpia should be about ½ inch in diameter. Put the lumpia on a lined baking sheet lined with parchment.

The lumpia can be made to this point and refrigerated, covered with a damp towel, for up to 8 hours or frozen in an airtight container.

Heat the oil in a Dutch oven over medium heat until it reaches 350 degrees on a deep-fry thermometer.

Line another lined baking sheet with paper towels. Fry the lumpia in batches of 4 to 6, until golden brown and crispy and the meat is cooked through, for a total of 4 minutes for fresh lumpia and 6 minutes for frozen.

Remove with a slotted spoon to the prepared baking sheet. Serve with sweet chili sauce on the side.

Note: I find that it helps to separate the wrappers in advance; cover them with a damp paper towel to prevent them from drying out.