Chop the pork and shrimp and put them in a large bowl.
Add cornstarch, palm sugar, fish sauce, salt, black pepper, and egg to the bowl, and stir the ingredients until well mixed.
Add garlic, shallots, lemongrass, cilantro, and scallions, and stir the ingredients again until well blended.
Let the mixture rest in the refrigerator for at least 30 minutes to allow the flavors to meld and the cornstarch to bind the ingredients together.
Remove the mixture from the refrigerator and shape small sausages about 5-7 cm long and 3 cm thick around the bamboo skewers - each chao tom should weigh about 30-40g.
Grill or fry chao tom on a pan or grill for about 5-7 minutes, or until they are golden and cooked through.
Serve chao tom warm with salad and dipping sauce.