Combine blueberries, lemon zest, and brandy in jar and seal tightly. Let sit in a cool dark place, shaking jar daily, until mixture is a deep purple color, about 1 month.  You can also substitute your favorite Vodka instead of Brandy.  If you don’t want to wait the month sous vide in a mason jar @ 135 degrees for 3 hours!  

Strain mixture through cheesecloth into a pitcher or large bowl (do not press on solids or mixture will become cloudy) and add simple syrup to taste. Chill until cold, about 30 minutes. Serve cordial in small glasses.

To make a spritzer, place 1 oz. cordial in a flute and top off with sparkling wine. Refreshing for barbeques or relaxing on your deck with friends.

Do Ahead: Strained cordial mixture can be made 6 months ahead. Cover and keep chilled.