This jelly is a variation on rose-petal jelly, a delicacy popular in the Balkans, Turkey, and Iran. Mint adds depth to the subtle flavor of violets. Try it with scones or as a pastry glaze.
Place flowers and mint in a small saucepan with 2 cups water. Bring to a boil, remove from heat, and let steep for 20 minutes. Strain through a fine-mesh sieve or a colander linedwith cheesecloth, and reserve liquid.
Pour liquid into a large heavy saucepan, and stir in vinegar and sugar. Bring to a boil over medium-high heat, and cook, stirring constantly, until sugar is dissolved, about 10 minutes. Add pectin, and bring to a boil. Boil for 1 minute, and remove from heat. Skim off any foam that has collected on top.
Ladle jelly into hot sterilized jars; seal. Let cool, and refrigerate up to 2 months, or freeze for up to 1 year.