How to Make It
In a small dish, soak the hot pepper in the vinegar for 2 minutes.
In a small bowl, combine the fish sauce, lime juice, carrot, garlic and sugar. Stir in 1 1/2 cups warm water and the hot pepper-vinegar mixture. Stir until the sugar dissolves. Serve at room temperature. Store the sauce in a jar in the refrigerator for up to 3 days.
Nuoc mam is available at Asian markets.