How to Make It
Preheat the oven to 425°. On a large rimmed baking sheet, toss the brussels sprouts with 2 tablespoons of the olive oil and season with salt. Spread in an even layer and roast for about 25 minutes, stirring occasionally, until softened and browned.
In a small bowl, whisk the remaining 1 tablespoon of olive oil with the fish sauce and vinegar. Drizzle the sauce over the warm brussels sprouts. Transfer to a platter, sprinkle with chopped peanuts and serve.