Step 1

Combine blackberry syrup ingredients in a saucepan and boil for 2 minutes. Remove from heat and let cook 10 minutes. Strain through a sieve and discard seeds and pulp. You should have about 1 3/4 cups blackberry syrup. Refrigerate to cool.

Step 2

In a pitcher combine: blackberry syrup, fresh lime juice and add 4 cups cold water, or add water to taste. Serve over ice garnished with lime slices if desired.