1. combine the lemongrass, soy sauce, chilies and sugar in a bowl. add the tofu cubes and turn to coat them
evenly. marinate for 30 minutes.
2. heat 2 tbsp of oil in a 12-inch nonstick skillet over moderately high
heat. add the onion, shallot and garlic and stir until fragrant, about
1 minute. reduce the heat to low and cook until the onions are soft,
about 3 minutes. transfer to a plate and keep warm.
3. wipe the pan clean and heat 2 tbsp of oil over moderate heat. add
the tofu marinade and, using chopstick or wooden spoons, turn so it
cooks evenly, about 4 to 5 minutes. add the onion mixture and cook,
uncovered, for another 2 to 3 minutes. add half the peanuts and all the
pepper leaves.
4. remove from the heat and transfer to a serving plate. garnish with the remaining peanuts and serve immediately with steamed rice.