Place the thyme sprig in the palm of your hand and slap it to release its oils.
Twist it and place in the bottom of a 10-ounce highball or Old Fashioned glass.
Fill with ice and set aside.
In a shaker, muddle the blueberries and lemon. (If blueberries are out of season, use 2 tsp of high-quality blueberry preserves instead. Adjust the amount of agave nectar depending on the sweetness of the preserves.).
Add the vodka, the agave nectar and ice, and shake vigorously for 10 to 20 seconds.
Strain into the prepared glass.
Slap a sprig of thyme in your hand and use as garnish.