- 3 tablespoons fish sauce (such as nam pla or nuoc nam)
 - 2 tablespoons water
 - 1 1/2 tablespoons (packed) golden brown sugar
 - 1/2 teaspoon ground black pepper
 - 2 tablespoons (1/4 stick) butter
 - 2 tablespoons olive oil, plus additional for brushing corn
 - 1 tablespoon thinly sliced green onions, white part only (from about 3)
 - 6 ears of corn, husked
 
- Stir first 4 ingredients in small bowl until sugar dissolves. Melt butter with 2 tablespoons oil in small saucepan over medium heat. Add fish sauce mixture and green onions and simmer until sauce begins to thicken, about 2 minutes.
 - Do ahead: Butter sauce can be made 2 hours ahead. Let stand at room temperature.
 - Preheat barbecue (medium-high heat). Brush corn with oil. Grill corn until tender and charred in spots, about 13 minutes. Brush corn generously with butter sauce and serve, passing remaining sauce separately.
 - Fish sauce is a versatile ingredient. Try it (1) mixed with garlic and cilantro as a marinade for grilled chicken; (2) in barbecue sauce for ribs; (3) in a salad of slivered green apples and chopped cilantro; and (4) in a compound butter with cayenne and shallots for grilled fish. It is available in the Asian foods section of many supermarkets and at Asian markets.