Line an 8x8 inch pan with foil. Spray the foil with non-stick spray.
In a 2-qt. saucepan, mix pectin, juice, and baking soda (mixture will be foamy). In a 3 quart saucepan, mix corn syrup and 1 cup of sugar. Place both saucepans over high heat at the same time, stirring both mixtures frequently. Cook about 4 minutes or until foam thins from pectin mixture and sugar mixture comes to a full rolling boil (a boil that does not stop bubbling when stirred).
Gradually add pectin mixture to boiling sugar mixture, stirring constantly. Boil 1 minuted, stirring. Remove saucepan from heat; stir in food coloring, if using. Immediately pour into prepared pan. Let stand at room temperature for 4 hours or overnight until firm.
Sprinkle waxed paper with 2 tablespoons sugar. Invert candy onto waxed paper and discard foil. Sprinkle top of candy with 2 more tablespoons sugar. Cut into 6 strips, then into 6 squares. Add 2 more tablespoons sugar and toss candy to coat all sides. Place candies on a wire rack. Let stand at room temperature overnight. Store tightly covered with waxed paper between layers of candy.