Heat the puree over medium-high heat in a saucepan fitted with a candy thermometer. Mix the pectin with half the sugar to "dilute" it. When the puree reaches 100 degrees F, add the pectin/sugar. Bring to a boil, stirring constantly. Add the remaining sugar and the corn syrup and cook until the mixture reaches 225 degrees F, stirring slowly and constantly with a rubber spatula, making sure to scrape the bottom and sides.
Dissolve the ascorbic acid in 1 teaspoon of water. Remove the pan from the heat and stir in the ascorbic acid. Pour into a baking dish lined with a silpat or parchment paper, and let set for at least overnight, until gelled and firm. Cut neatly into rectangles 1-inch by 1 1/2 inches. Spread a few tablespoons of sugar in a dish and roll each square in sugar, to coat. Wrap individually in cellophane or store in an airtight container. At room temperature, they keep up to 4 weeks.
Notes about the recipe: When golden-brown cookies and dark-brown chocolates threaten to overwhelm my petit-four trays, I can always depend on the bright garnet sparkle of these candies, lively in color and flavor. In France, where I learned to make them, gelees come in a tremendous range of colors and flavors, from grass-green kiwi to deep purple blackberry.
And if you're a fan of Chuckles candies, these will blow your mind. Pectin is a natural fruit gelatin that you can buy in powder form, especially during canning season (June-October). Ascorbic acid, a natural antioxidant available at health-food stores, keeps the color bright.