In a pot combine stock, shallots, lemongrass, garlic, and rice and bring to a simmer. Cook until soup is thickened and rice is tender, about 20 minutes. Reduce heat to low Remove lemongrass and discard.

Add ground pork and stir, breaking up the pork, until pork is fully cooked, about 2 minutes. Add fish sauce, a pinch of salt, and lime juice. Stir in half of cilantro, half of scallions, half of chili, and all of the tofu. Add more fish sauce and salt to taste.

Divide soup between bowls, then top with remaining cilantro, scallions, chilies, tofu, and fried shallots. Serve immediately.