Place zest and sugar in a small bowl. Mash and mix together with the back of a wooden spoon or a pestle. Continue mashing until sugar is absorbed into the orange zest and is no longer distinct. Place into aging container. Add cognac. Stir, cap and let age in a cool dark place 2 to 3 months, shaking monthly. After initial aging, pour through fine mesh strainer placed over medium bowl. Rinse out aging container. Pour glycerine into aging container and place cloth bag inside strainer. Pour liqueur through cloth bag. Stir with a wooden spoon to combine. Cap and age 3 more months before serving.