In a small saucepan over medium heat, whisk the cornstarch and cranberry juice until the cornstarch has dissolved and the mixture is very thick, about 1 minute.

Whisk in corn syrup and adjust the heat to low. Cook, whisking frequently, until the syrup thickens, about an additional 2 minutes. Remove from heat and whisk in the food coloring until you have the desired color.

Remove to a bowl or resealable container and let cool completely. Store in the refrigerator for up to 3 weeks. If needed, add a few drops of cranberry juice or water to thin the mixture after refrigerating.

Add to a shallow dish or plate and dip the cocktail glasses into the syrup. Turn the glasses over to let the syrup drip down the rim.

In a cocktail shaker filled with ice, add the vodka, cranberry juice, Chambord, lemon juice and simple syrup.