2 stalks fresh lemon grass, or 2 tablespoons dried lemon grass
1 pound lean beef filet or eye of round
2 fresh red chile peppers, seeded and minced
6 garlic cloves, minced
3 tablespoons nuoc mam (Vietnamese fish sauce)
1 teaspoon arrowroot or cornstarch
freshly ground black pepper
6 tablespoons vegetable oil
2 medium onions, cut into slivers
1 tablespoon sugar
1/4 cup roasted peanuts coarsely ground
coriander sprigs, for garnish
If you are using fresh lemon grass, discard the outer leaves and upper half of the stalk. Slice paper-thin and chop very fine. If you are using dried lemon grass, soak in warm water for 1 hour. Drain and chop very fine.
Cut the beef across the grain into very thin 2 by 3-inch slices. Pound the meat lightly with the flat side of a cleaver.
In a bowl, combine the beef with the lemon grass, chiles, half of the garlic, 2 tablespoons of the fish sauce, the arrowroot, black pepepr to taste and 2 tablespoons of the oil. Mix well. Set aside for 30 minutes.
Heat a large skillet over moderately high heat and add 2 tablespoons of the oil. When the oil is hot, add the onions and the remaining garlic; stir-fry for about 3 minutes, or until golden brown. Remove the onions with a slotted spoon to a plate. Add the remaining 2 tablespoons oil. When the oil is hot, add the beef, the remaining 1 tablespoon fish sauce and the sugar. Saute over high heat for 1 or 2 minutes, or until the beef is just cooked. Transfer the mixture to a heated platter.
Arrange the sauteed onions around the meat mixture; sprinkle the peanuts and black pepper over all. Garnish with coriander.