This version of the traditional pate de coing (quince paste) was formed in a classic French mold, the results frost-encrusted with sugar.
In a small bowl, combine pectin with 1/2 cup sugar; set aside. Have ready an 11-by-17-inch baking pan and a 1-cup mold.
Wash, peel, quarter, and core pears. Place pears and cranberries in the bowl of a food processor. Puree until fine.
Transfer puree to a six-quart saucepan, and add remaining 3 1/2 cups sugar. Bring to a boil over medium-high heat, stirring to dissolve sugar. Reduce heat to medium low, and simmer 3 minutes.
Sprinkle pectin mixture over pear mixture, whisking constantly. Increase heat to medium high, and return mixture to a boil. Cook, whisking, 2 minutes. Remove from heat, and, working quickly, immediately pour mixture into baking pan and mold. Tap pan on countertop to smooth surface, and transfer pan to a wire rack until completely cool.
With the baking pan, use cookie cutters or a paring knife to cut fruit paste into decorative shapes. To unmold fruit paste from the mold: Carefully dip mold into a pan of simmering water; hold about 10 seconds. Tap all four sides on tabletop to break air seal. Invert mold over a serving plate, and let sit until paste releases. If necessary, tap again. Cover with plastic, and store in a dry, cool place.
Before serving, pour sugar into a bowl, and roll shapes in sugar, covering completely.