How to Make It
In a small bowl, mix the sliced shallots with the vinegar and a generous pinch of salt.
In a bowl, mix the pork with the egg, lemongrass, minced shallots and cilantro, fish sauce, cornstarch, garlic and 1 1/2 teaspoons of salt. Cover and refrigerate for 30 minutes. Form into 1 1/2-inch balls.
In a large skillet, heat the oil. Add the meatballs and cook over moderate heat until browned and cooked through, 8 to 10 minutes. Transfer to a platter and serve in Bibb lettuce leaves with the pickled shallots and garnishes.