Can be prepared in 45 minutes or less.

Ingredients

　　1/3 cup water or brewed coffee

　　1/2 cup firmly packed dark brown sugar

　　1/2 cup unsweetened Dutch-process cocoa powder

　　1/8 teaspoon salt

　　2 tablespoons unsalted butter, cut into pieces

　　1/2 teaspoon vanilla

　　In a heavy saucepan hat the water or coffee with the brown sugar over moderate hat, whisking until the sugar is dissolved, add the cocoa powder and the salt, and whisk the mixture until it is smooth. Add the butter and the vanilla and whisk the sauce until the butter is melted. Serve the sauce warm over ice cream.