Beginner's Fudge

1/4 cup orange juice6 tablespoons unsalted butter1 1/2 cups miniature marshmallows2 cups (12 ounces) semisweet chocolate chips1 1/2 cups walnuts, coarsely choppedLightly butter the bottom of a 7-by-11-inch baking pan. Set aside.In a large saucepan over medium heat, combine orange juice, butter and marshmallows. Whisk constantly just until marshmallows completely melt and mixture becomes hot. Do not bring to boil. Cool 1 minute.Add chocolate chips and briskly stir with wooden spoon until chocolate is melted and smooth. Do not overmix. (If chocolate mixture seizes and becomes grainy, stir in 2 tablespoons vegetable oil.) Fold in walnuts. Spoon into pan and gently smooth top. Cover and chill 24 hours until firm and set. Flavor improves and develops after chilling for 1 day.Store two weeks refrigerated. Cut into pieces while cold and serve at room temperature.Makes 3 dozen pieces.Baker's hint: Substitute 12 large marshmallows for the miniature variety.Nutrition values per piece: 99 calories, 8 g fat (3 g saturated), 2 g protein, 8 g carbohydrates, 1 g fiber, 5 mg cholesterol, 2 mg sodium.