- Slice bottom 6 inches of lemongrass, discard remainder. Place in food processor or blender with shallot, garlic, cumin and ¼ cup water. Process until smooth.
- Place medium skillet over medium heat until hot. Add oil, swirling to coat sides. Add spice mixture, and cook, stirring often, until fragrant, 6 to 8 minutes.
- Add 1 cup water, peanuts, brown sugar, chili sauce and soy sauce; stir until blended. Bring to a boil. Reduce heat, and simmer until sauce is slightly thickened, 5 minutes.