1. Heat sesame oil in wok or large pan. Add lemon grass, being sure to discard the most fibrous parts, and cook for 5-7 minutes. Meanwhile, wrap tofu block in a dish towel and put a weight on top, so that extra water is pressed out.
2. Add chili peppers. Use less if you don't like it spicy, or take out the seeds. Add lime rind, vegetable bouillon, powdered galangel, and shallots. Cook until shallots become translucent and lemongrass is edible.
3. Add garlic and raw peanuts. Cook for 4 minutes.
4. Add chopped tofu and mix. Squeeze the lime juice into the mixture. Cook for 5 minutes or so, letting the extra water escape.
5. Add scallions, cilantro, and mint (if using). Cook until wilted and hot.
6. Serve on a bed of lettuce, with fresh tomato slices and hot rice on the side.
Source of recipe: This recipe was inspired by the wonderful Thai restaurant, Esan Thai Restaurant, in Bloomington, Indiana. They offer this dish with tofu and meat, but all the recipes I have been able to find used meat and even otherwise were never were quite right. After experimenting, this at least approximates the taste of their dish. I read that "larb" simply means "salad."