In a heavy saucepan, combine the sugar, water and food coloring if desired. Bring to a boil over medium heat; stir in peanuts. Cook, stirring occasionally, for 12 minutes or until peanuts are coated and no syrup remains. Spread peanuts into an ungreased 15x10x1-in. baking pan; separated with a fork. Bake at 300° for 30 minutes, stirring every 10 minutes. Cool. Store in an airtight container at room temperature.